Chandra X-Ray Observatory
	(CXC)

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List of DDT Observations


Please note that obs_start_time is in UT, not local time.

Clicking on the Sequence Number link will take you to the title and abstract of the proposal.

Clicking on the ObsID link will take you to the results of our search in ADS for articles we were able to link to the ObsID. Our database extends to publications that appeared three months or more ago and does not include meeting abstracts.

A 'D' in the prop_time column means a proprietary time of 1-3 months, with the default being 3 months. A '3' means a proprietary time of three months. An 'N' means the data is public.

Click here for table only

CycleSequence NumberObsIDInstrumentGratingApproved Exposure TimeActual Exposure TimeTargetStatusApproval DateStart Time [UT]Proprietary TimePI Name
    
1850297320055ACIS-SNONE50.00000050.956999SN2017cbvscheduled Mar 23 2017 2:47PM  Mar 27 2017 11:54AM DDrout
1840189220054ACIS-INONE65.0000000.000000PSRB1259-63unobserved Mar 17 2017 11:23AM  NPavlov
1870346620035ACIS-SNONE14.4000000.000000M87unobserved Feb 27 2017 7:29PM  NNeilsen
1870346620034ACIS-SNONE14.4000000.000000M87unobserved Feb 27 2017 3:14PM  NNeilsen
1870346520021ACIS-SNONE10.00000010.049712WPVS007archived Feb 16 2017 5:44PM  Mar 16 2017 3:24PM NGrupe
1840189120008ACIS-SHETG30.00000030.071250GRS1716-249observed Jan 31 2017 1:22PM  Feb 6 2017 12:24PM DMiller
1810016820002HRC-INONE36.0000000.000000Jupiterunobserved Jan 26 2017 2:50PM  NJackman
1810016720001HRC-INONE36.0000000.000000Jupiterunobserved Jan 26 2017 2:50PM  NJackman
1810016620000HRC-INONE72.00000072.138735Jupiterarchived Jan 26 2017 2:50PM  Feb 28 2017 12:53PM NJackman
1850297219999ACIS-SNONE10.0000009.978900iPTF17cwobserved Jan 23 2017 5:25PM  Feb 8 2017 9:39AM DCorsi
1770346419990ACIS-SNONE30.00000030.090000SDSSJ140737.16+4428observed Jan 11 2017 10:36AM  Feb 25 2017 2:51PM DSecrest
1750297119986ACIS-SNONE30.0000000.000000CSS161010unobserved Dec 21 2016 4:13PM  DMargutti
1750297019985ACIS-SNONE30.00000027.416074CSS161010observed Dec 21 2016 4:13PM  Feb 13 2017 12:16PM DMargutti
1750296919984ACIS-SNONE30.00000030.045200CSS161010observed Dec 21 2016 4:13PM  Jan 13 2017 11:32PM DMargutti
1730040119983HRC-SLETG50.00000050.185284ASSASN-16ohobserved Dec 19 2016 2:25PM  Dec 28 2016 9:27PM DMaccarone
1740189019904ACIS-SHETG30.00000031.0527504U1630-47archived Oct 6 2016 2:17PM  Oct 21 2016 1:43AM DBhattacharyya
1740188919891ACIS-SNONE35.00000036.302609CXOUJ103844.8+53300archived Sep 22 2016 2:40PM  Oct 22 2016 4:32PM NEarnshaw
1720115419793HRC-INONE11.25000010.889601ProximaCenarchived Sep 6 2016 5:03PM  Dec 8 2016 8:29PM NWargelin
1720115319790HRC-INONE11.25000010.889729ProximaCenarchived Sep 1 2016 4:40PM  Nov 3 2016 6:43PM NWargelin
1720115219789HRC-INONE11.25000010.922401ProximaCenarchived Sep 1 2016 4:40PM  Oct 14 2016 6:31PM NWargelin
1720115119788HRC-INONE11.25000012.464001ProximaCenarchived Sep 1 2016 4:40PM  Sep 26 2016 8:12AM NWargelin
1740188819787ACIS-SHETG15.00000015.040450SMCX-3archived Aug 30 2016 11:23AM  Sep 7 2016 4:45PM DCoe
1740188819786ACIS-SHETG25.00000024.042227SMCX-3archived Aug 30 2016 11:18AM  Sep 6 2016 7:50PM DCoe
1740188119691ACIS-INONE1.0000001.081900SWIFTJ003233.6-7306archived Aug 3 2016 2:10PM  Aug 11 2016 11:00PM DKennea
1750296319690ACIS-SNONE60.00000056.230900PSRJ1119-6127archived Aug 2 2016 6:22PM  Oct 27 2016 6:38PM NBlumer
1730039218889ACIS-SNONE18.00000018.027750FOAqrarchived Jul 14 2016 11:46AM  Jul 26 2016 7:26AM NKennedy
1740181918885ACIS-SNONE25.00000025.535198XMMUJ004855.5-73494archived Jun 30 2016 11:04AM  Jul 6 2016 8:43AM NVasilopoulos
1750266718884ACIS-SNONE20.00000020.069599SGR1935+2154archived Jun 29 2016 3:51PM  Jul 7 2016 5:43AM DKouveliotou
1750266618880ACIS-SNONE30.00000029.047000Gaia16apdobserved Jun 27 2016 12:27PM  Mar 19 2017 5:29PM DYan
1750266518879ACIS-SNONE30.00000030.032422Gaia16apdarchived Jun 27 2016 12:27PM  Oct 23 2016 6:11PM DYan
1750266418878ACIS-SNONE47.00000044.1855001E161348-5055archived Jun 23 2016 2:38PM  Jun 25 2016 9:30AM DRea
1750266318827ACIS-SNONE15.00000015.081000SN2016bkvarchived Apr 1 2016 1:03PM  Apr 20 2016 4:10AM NPatnaude
1740181818815ACIS-SNONE30.00000030.090000HETEJ1900.1-2455archived Mar 17 2016 5:15PM  Apr 18 2016 10:09PM DDegenaar
1770330118813ACIS-SNONE5.0000005.068768M87archived Mar 9 2016 8:02PM  Mar 17 2016 3:43AM NCheung
1770330018812ACIS-SNONE5.0000004.853443M87archived Mar 9 2016 8:02PM  Mar 16 2016 12:27AM NCheung
1770329918811ACIS-SNONE5.0000005.069200M87archived Mar 9 2016 8:02PM  Mar 14 2016 1:44PM NCheung
1770329818810ACIS-SNONE5.0000005.069600M87archived Mar 9 2016 8:02PM  Mar 13 2016 7:25AM NCheung
1770329718809ACIS-SNONE5.0000004.984400M87archived Mar 9 2016 8:02PM  Mar 12 2016 5:07AM NCheung
1770329618804ACIS-SNONE30.00000030.062316QSO2237+0305archived Mar 9 2016 1:39PM  Apr 24 2016 5:27AM NPooley
1750266218802ACIS-SNONE36.00000036.062177SN2005iparchived Mar 2 2016 12:16PM  Apr 4 2016 2:16AM NMauerhan
1730039118800ACIS-SNONE25.00000025.103556MWC560archived Feb 25 2016 5:26PM  Mar 9 2016 2:20AM DLucy
1730039118790ACIS-SNONE25.00000025.101000MWC560archived Feb 23 2016 2:41PM  Mar 8 2016 7:17AM DLucy
1770329518789ACIS-SNONE30.00000029.978798Mrk1018archived Feb 18 2016 12:45PM  Feb 25 2016 2:37AM DTremblay
1740181718788ACIS-SNONE5.0000004.956140PSRJ2032+4127archived Feb 15 2016 5:13PM  Feb 24 2016 8:23AM NHo
1750266118760ACIS-SNONE5.0000005.025100ASASSN16atarchived Jan 26 2016 11:14AM  Feb 6 2016 6:57AM NGrupe
1620108418725ACIS-SNONE20.00000020.094000HD97658archived Dec 3 2015 10:31AM  Mar 5 2016 4:21PM DWheatley
1620108418724ACIS-SNONE20.00000020.094000HD97658archived Dec 3 2015 9:52AM  Dec 11 2015 1:01PM DWheatley
1650266018717ACIS-SNONE40.00000040.092000FRB121102archived Nov 19 2015 11:14AM  Nov 23 2015 10:37AM DScholz
1640181618686HRC-SNONE2.8000002.938931SMCX-2archived Oct 1 2015 5:25PM  Nov 5 2015 6:56PM NLi
1670328018352ACIS-SNONE10.00000010.124600NGC660archived Jul 22 2015 3:32PM  Aug 26 2015 8:37PM NAnnuar
1610015517709ACIS-SNONE110.000000107.221501Pluto(134340)archived Jul 15 2015 3:19PM  Aug 1 2015 9:30PM NMcNutt
1610015517708ACIS-SNONE16.00000017.595600Pluto(134340)archived Jul 15 2015 3:19PM  Jul 30 2015 5:30AM NMcNutt
1640169817704ACIS-SNONE28.00000028.752000V404Cygarchived Jul 14 2015 3:56PM  Jul 25 2015 6:46PM NHeinz
1610015517703ACIS-SNONE14.00000014.088741Pluto(134340)archived Jul 9 2015 1:59PM  Jul 27 2015 12:09AM NMcNutt
1640169717701ACIS-SHETG40.00000040.035879V404Cygarchived Jul 2 2015 3:23PM  Jul 11 2015 1:17PM NNeilsen
1640169617697ACIS-SHETG25.00000024.712915v404Cygarchived Jun 22 2015 7:37PM  Jun 23 2015 9:40PM NKing
1640169517696ACIS-SHETG30.00000029.307864v404Cygarchived Jun 19 2015 9:29AM  Jun 22 2015 1:56PM NKing
1640169417678ACIS-INONE10.00000010.102500M82archived Jun 5 2015 2:09PM  Jun 21 2015 3:12AM NBrightman
1650249317673ACIS-SNONE10.00000010.061636SNhunt275archived May 26 2015 3:17PM  Sep 20 2015 11:42PM NMargutti
1650249217672ACIS-SNONE10.00000010.046760SNhunt275archived May 26 2015 3:17PM  Jun 8 2015 2:04AM NMargutti
1640169317662ACIS-INONE5.0000005.0809002S1553-542archived May 13 2015 4:36PM  May 21 2015 4:53PM DLutovinov
1640169217661HRC-SNONE30.00000029.765233SAXJ1808.4-3658archived May 11 2015 2:47PM  May 24 2015 10:29PM DPatruno
1650249117658ACIS-SNONE25.00000023.643700GRB150423Aarchived Apr 28 2015 3:13PM  May 2 2015 7:39AM NBerger
1640169117649ACIS-SHETG30.00000030.0730001RXSJ180408.9-34205archived Apr 7 2015 1:46PM  Apr 14 2015 3:08PM DDegenaar
1630033817648ACIS-SHETG35.00000034.947201GKPerseiarchived Mar 29 2015 7:31AM  Apr 4 2015 8:21AM NOrio
1620102617644ACIS-SNONE40.00000038.690798RWAurarchived Mar 20 2015 3:47PM  Apr 16 2015 6:56AM NSchneider
1650249017639ACIS-SNONE50.00000047.108715CasACCOarchived Mar 9 2015 4:35PM  May 1 2015 2:18AM NPosselt
1640169017637ACIS-SNONE10.00000010.075000[PFH2005]622archived Mar 4 2015 2:19PM  Mar 6 2015 4:48PM NBurrows
1670315517636ACIS-SNONE10.00000010.056400WPVS007archived Mar 4 2015 9:08AM  Mar 28 2015 8:20AM NGrupe
1640168917631HRC-INONE10.00000010.1536511817-0454archived Feb 15 2015 11:51PM  Feb 18 2015 4:11AM DPetroff
1640168817630ACIS-SHETG15.00000014.4576004U1700-37archived Feb 12 2015 5:51PM  Feb 22 2015 3:30AM NOskinova
1670315417594ACIS-SNONE15.00000015.058837SwiftJ123205.1-1056archived Jan 14 2015 5:56PM  Feb 10 2015 5:35AM NLevan
1650248917586ACIS-SNONE15.00000015.066000SwiftJ123205.1-1056archived Jan 6 2015 2:57PM  Jan 9 2015 11:55AM NTroja
1550248817571ACIS-SNONE10.00000010.056279SN2014Carchived Dec 15 2014 12:02PM  Aug 28 2015 9:03AM NMargutti
1550248717570ACIS-SNONE10.00000010.024851SN2014Carchived Dec 15 2014 12:02PM  Apr 20 2015 10:47PM NMargutti
1550248617569ACIS-SNONE10.00000010.045655SN2014Carchived Dec 15 2014 12:02PM  Jan 30 2015 3:22PM NMargutti
1570315217567HRC-SLETG45.00000044.793784ASASSN-14liarchived Dec 4 2014 5:21PM  Dec 11 2014 9:09AM NMiller
1570315217566HRC-SLETG35.00000035.039883ASASSN-14liarchived Dec 4 2014 4:24PM  Dec 8 2014 11:29PM NMiller
1540168617559ACIS-SNONE40.00000040.114000CXOJ122518.6+144545archived Nov 26 2014 11:33AM  Dec 15 2014 6:27AM DHeida
1540168517558ACIS-SNONE20.00000019.985700CXOJ122518.6+144545archived Nov 26 2014 11:33AM  Dec 8 2014 5:42PM DHeida
1550248517550ACIS-SNONE20.00000020.058751PSNJ12215757+042818archived Nov 4 2014 4:44PM  Nov 16 2014 3:28PM NMargutti
1570315117547ACIS-SNONE5.0000005.071600NGC247archived Oct 22 2014 11:11AM  Nov 12 2014 5:54AM DFeng
1570315017538ACIS-SNONE20.00000020.078069SDSSJ152304.97+1145archived Sep 26 2014 9:55AM  Dec 26 2014 4:59AM DGallo
1550247917314ACIS-SNONE30.00000029.154750SGR1935+2154archived Aug 7 2014 3:43PM  Aug 31 2014 12:59AM DRea
1520096816631ACIS-SNONE25.00000023.011038V1180Casarchived Jun 20 2014 3:48PM  Aug 2 2014 10:11PM NNucita
1540161516625ACIS-SNONE5.0000005.147250PSRB1259-63archived Jun 16 2014 12:48PM  Jun 25 2014 7:03PM NBordas
1540161416624ACIS-SNONE5.0000005.174750PSRB1259-63archived Jun 16 2014 12:48PM  Jun 23 2014 6:46PM NBordas
1550227116618ACIS-SNONE20.00000020.063200GRB140515Aarchived May 20 2014 1:07PM  May 25 2014 7:54AM NMargutti
1540161316606ACIS-SHETG35.00000035.082250GROJ1744-28archived Mar 22 2014 7:58PM  Mar 31 2014 12:48AM DMiller
1540161316605ACIS-SHETG35.00000035.073250GROJ1744-28archived Mar 22 2014 6:28PM  Mar 29 2014 7:09PM DMiller
1540161216596ACIS-SHETG10.00000010.077500GROJ1744-28archived Feb 17 2014 5:12PM  Mar 3 2014 9:15AM DKennea
1440161116583ACIS-INONE30.00000028.538149PSRB1259-63archived Jan 23 2014 6:17PM  Feb 9 2014 7:49AM NPavlov
1550226916580ACIS-SNONE50.00000047.465954SN2014Jarchived Jan 23 2014 12:03PM  Feb 3 2014 8:26PM NMargutti
1520096716577ACIS-SNONE10.0000009.964800KOI-314archived Jan 21 2014 1:27PM  Feb 7 2014 9:42PM DPoppenhaeger
1440161116563ACIS-INONE35.00000032.061376PSRB1259-63archived Dec 19 2013 4:13PM  Feb 8 2014 1:42PM NPavlov
1440161016561ACIS-SNONE30.00000030.578400XSSJ12270-4859archived Dec 16 2013 1:33PM  Jan 11 2014 5:14AM DPatruno
1450226816556ACIS-SNONE20.00000019.064984SN2013gearchived Dec 2 2013 12:21PM  Dec 7 2013 6:08PM NMargutti
1450226616488ACIS-SNONE50.00000046.073786GRB130925Aarchived Oct 1 2013 2:36PM  Oct 6 2013 4:22AM DBellm
1450226516441ACIS-SNONE15.00000015.069100GRB130831Aarchived Sep 9 2013 3:31PM  Oct 3 2013 1:27PM DDePasquale
1450226416440ACIS-SNONE15.00000014.641300GRB130831Aarchived Sep 9 2013 3:31PM  Sep 17 2013 1:21AM DDePasquale
1450203715663ACIS-SNONE30.00000029.964800GRB130606Aarchived Jun 12 2013 10:10AM  Jun 17 2013 3:29AM DBerger
1460109915648ACIS-SNONE25.00000025.062680CXOUJ072648.3+85454archived May 9 2013 3:19PM  May 24 2013 12:22PM NRoberts
1470292315647ACIS-SHETG30.00000030.554400Mrk590archived May 2 2013 9:55AM  Jun 16 2013 7:33AM NMathur
1440154115646ACIS-SNONE15.00000013.753555NGC404archived Apr 26 2013 5:16PM  Jun 4 2013 2:44AM NKaaret
1440154015645HRC-SNONE53.00000053.041959IGRJ18245-2452archived Apr 26 2013 10:08AM  Apr 29 2013 12:24AM DPatto
1410009515641ACIS-SNONE5.0000005.183200Comet2011L4(PANSTarchived Mar 20 2013 4:41PM  Apr 24 2013 12:47AM NLisse
1410009415640ACIS-SNONE5.0000005.180100Comet2011L4(PANSTarchived Mar 20 2013 4:39PM  Apr 21 2013 2:39PM NLisse
1410009315639ACIS-SNONE5.0000005.177000Comet2011L4(PANSTarchived Mar 20 2013 4:38PM  Apr 17 2013 9:44AM NLisse
1470292215637ACIS-SNONE15.00000015.0691002XMMIJ184725.1-6317archived Mar 18 2013 5:51PM  Mar 29 2013 4:28AM DLin
1410009715631HRC-INONE5.0000005.181632Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 24 2013 2:21AM NLisse
1410009615630HRC-INONE5.0000005.189832Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 17 2013 11:17AM NLisse
1410009515629ACIS-SNONE5.0000005.071600Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 23 2013 11:15PM NLisse
1410009415628ACIS-SNONE5.0000005.074700Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 21 2013 1:07PM NLisse
1410009315627ACIS-SNONE5.0000005.070699Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 17 2013 8:12AM NLisse
1490109515625ACIS-SNONE10.0000009.964770NuSTARJ163433-47384archived Mar 11 2013 3:12PM  Mar 23 2013 8:46AM DTomsick
1430031815620HRC-INONE5.0000005.179582M31N2013-01barchived Mar 1 2013 12:52PM  Mar 11 2013 11:16PM NHenze
1450203215616ACIS-SNONE2.0000002.064600M82transientarchived Feb 11 2013 5:01PM  Feb 24 2013 11:25PM NMadej
1320091015597ACIS-SNONE25.00000025.074440MLS121106:014420+082archived Nov 19 2012 8:10PM  Nov 23 2012 5:02PM DVianello
1330031715596HRC-SLETG25.00000025.119933NovaMon2012archived Nov 19 2012 2:11PM  Dec 3 2012 8:01PM NOrio
1370292015584ACIS-SNONE25.00000024.966258Swift-J1644+57archived Nov 1 2012 10:24AM  Nov 26 2012 10:25AM NTanvir
1330031615495ACIS-SHETG25.00000025.049135PNVJ06393874+055352archived Aug 29 2012 4:40PM  Sep 12 2012 9:13AM NNess
1350202115268ACIS-SNONE20.00000020.068815GRB120804Aarchived Aug 7 2012 2:47PM  Aug 13 2012 11:11AM NTroja
1350202015265HRC-INONE10.00000010.1241821E2259+586archived Jul 31 2012 12:04PM  Aug 21 2012 4:51PM DKas
1350180014464ACIS-SNONE10.00000010.068800GRB120624Barchived Jun 28 2012 11:30AM  Jun 30 2012 9:24AM NCampana
1340143514442ACIS-SNONE20.00000020.065073NGC4088ULX1archived May 25 2012 4:51PM  Jun 2 2012 3:30AM DMezcua
1340143414441ACIS-SHETG20.00000019.0732504U1630-47archived May 24 2012 2:28PM  Jun 3 2012 10:28PM DNeilsen
1340143014428ACIS-SHETG20.00000020.103500SwiftJ1753.5-0127archived Apr 26 2012 12:18PM  May 3 2012 3:25PM DSoleri
1330031214426HRC-SLETG20.00000020.189682NovaLMC2012archived Apr 17 2012 6:34PM  Apr 26 2012 10:12PM NDrake
1340142914425ACIS-SHETG30.00000030.088300MAXIJ1305-704archived Apr 16 2012 2:32PM  Apr 29 2012 7:20PM DMiller
1350179714420ACIS-SNONE20.00000020.398000PTF11qcjarchived Mar 28 2012 2:18PM  Apr 11 2012 8:55AM NCorsi
1350179614412ACIS-SNONE40.00000039.641600SN2011jaarchived Mar 13 2012 2:26PM  Apr 3 2012 5:10AM DRay
1320083014402ACIS-SNONE20.00000020.06959955Cncarchived Feb 23 2012 2:57PM  Apr 5 2012 1:03PM DWheatley
1320082914401ACIS-SNONE12.00000011.78639955Cncarchived Feb 23 2012 2:56PM  Mar 7 2012 2:11AM DWheatley
1350179414398ACIS-SNONE10.00000010.062600PTF11qcjarchived Feb 9 2012 12:09PM  Feb 26 2012 9:15AM NCorsi
1350179314382ACIS-SNONE10.0000009.961085PTF11qcjarchived Dec 27 2011 1:24PM  Jan 13 2012 1:43AM NCorsi
1340142714376ACIS-SNONE2.0000002.010400NGC891ULX1archived Dec 5 2011 4:45PM  Dec 20 2011 7:12AM NHodges-Kluck
1350179214360ACIS-SNONE20.00000021.010349CXOUJ164710.2-45521archived Oct 12 2011 11:14AM  Oct 23 2011 3:56PM DIsrael
1250179114341ACIS-SNONE40.00000049.715200PTF11klyarchived Aug 26 2011 10:09AM  Aug 27 2011 11:00AM NHughes
1240142514337ACIS-SHETG14.00000014.047270IGRJ17498-2921archived Aug 24 2011 8:50AM  Aug 29 2011 2:22PM NDiSalvo
1240142514336ACIS-SHETG16.00000016.345000IGRJ17498-2921archived Aug 19 2011 3:02PM  Aug 30 2011 1:36PM NDiSalvo
1250178914329ACIS-SNONE15.00000014.350399SwiftJ1834.9-0846archived Aug 11 2011 2:56AM  Aug 22 2011 3:46PM NKargaltsev
1250178814237ACIS-SNONE10.00000010.043925GRB110709Barchived Aug 3 2011 2:39PM  Oct 31 2011 8:15PM NLevan
1250156713511HRC-INONE1.0000001.181953SwiftJ1822.3-1606archived Jul 18 2011 2:48PM  Jul 28 2011 8:21PM DKouveliotou
1270258213423HRC-INONE5.0000005.187525SwiftJ2058archived Jun 13 2011 12:57PM  Jun 22 2011 3:04PM NCenko
1240130013420HRC-INONE1.0000001.530581M15X-2archived May 18 2011 4:15PM  May 30 2011 4:54PM NSivakoff
1250156313419ACIS-SNONE5.0000005.043424NewPWNCandidatearchived May 6 2011 2:58PM  Jun 2 2011 2:06PM NMiller
1270258113418ACIS-SNONE10.00000010.040058TDE_PS1_DDT_C12archived Apr 29 2011 10:54AM  May 22 2011 11:16PM NGezari
1240129713252ACIS-SNONE40.00000040.080000CXOGClbJ174804.8-24archived Mar 31 2011 10:28AM  Apr 29 2011 5:30PM DDegenaar
1220073513250ACIS-SLETG20.00000020.075300TWHyaarchived Mar 29 2011 4:23PM  Apr 13 2011 12:00PM NGuenther
1240129513237ACIS-SNONE40.00000040.077250HESSJ0632+057archived Feb 9 2011 2:40PM  Feb 13 2011 9:28PM DTorres
1240129313225ACIS-SNONE30.00000030.078000CXOGClbJ174804.8-24archived Jan 24 2011 2:02PM  Feb 17 2011 9:31AM DWijnands
1240129213219ACIS-SHETG12.00000012.000000CygX-1archived Jan 19 2011 9:47AM  Feb 5 2011 6:56AM NMcClintock
1250154913217ACIS-SNONE15.00000015.010343XTEJ1810-197archived Jan 12 2011 12:23AM  Feb 9 2011 12:04AM DPerna
1260098213212ACIS-SNONE10.00000010.186400NGC1589-OTarchived Dec 23 2010 3:54PM  Jan 16 2011 3:58AM NFilippenko
1250154813210ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Oct 15 2011 4:51AM NWeisskopf
1250154713209ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Sep 15 2011 4:09AM NWeisskopf
1250154613208ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Aug 15 2011 9:01AM NWeisskopf
1250154513207ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Apr 12 2011 2:15PM NWeisskopf
1250154413206ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Mar 15 2011 6:04AM NWeisskopf
1250154313205ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Feb 16 2011 4:52PM NWeisskopf
1250154213204ACIS-SNONE5.0000003.323628Crabarchived Dec 14 2010 12:26PM  Jan 15 2011 12:07AM NWeisskopf
1270251113203ACIS-SNONE16.00000016.046587ULASJ1120+0641archived Dec 13 2010 12:51PM  Feb 4 2011 12:08PM DSimpson
1240129113171ACIS-SNONE4.0000003.755348J192430.2+510146archived Oct 20 2010 9:21AM  Nov 7 2010 7:58AM DLiu
1240129013170ACIS-SNONE4.0000003.961600J194016.3+463251archived Oct 20 2010 9:21AM  Nov 7 2010 2:06PM DLiu
1240128913169ACIS-SNONE3.0000002.965220J192607.1+505252archived Oct 20 2010 9:20AM  Nov 12 2010 4:16PM DLiu
1240128813168ACIS-SNONE3.0000002.962514J190822.7+385101archived Oct 20 2010 9:20AM  Nov 12 2010 7:57PM DLiu
1240128713167ACIS-SNONE3.0000002.960000J191016.9+392951archived Oct 20 2010 9:20AM  Nov 7 2010 6:52AM DLiu
1240128613166ACIS-SNONE3.0000002.752000J193239.6+382518archived Oct 20 2010 9:20AM  Nov 4 2010 9:49PM DLiu
1240128513165ACIS-SNONE3.0000002.758400J192630.6+413314archived Oct 20 2010 9:20AM  Nov 4 2010 10:50PM DLiu
1240128413164ACIS-SNONE2.0000002.097700J194759.9+413111archived Oct 20 2010 9:20AM  Nov 14 2010 3:12AM DLiu
1240128313163ACIS-SNONE2.0000002.097586J191438.6+502857archived Oct 20 2010 9:20AM  Nov 7 2010 1:05PM DLiu
1240128213161ACIS-SHETG30.00000030.074000EXO1745-248archived Oct 15 2010 12:44PM  Oct 24 2010 11:03AM DBhattacharyya
1250154013154ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 28 2011 6:40AM NWeisskopf
1250153913153ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 21 2011 11:25PM NWeisskopf
1250153813152ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 16 2011 8:45AM NWeisskopf
1250153713151ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 14 2011 2:32PM NWeisskopf
1250153613150ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 13 2011 11:32PM NWeisskopf
1250153513149ACIS-SNONE15.00000015.459500XTEJ1810-197archived Oct 7 2010 10:30AM  Oct 25 2010 4:19AM DBernardini
1250153413148ACIS-SNONE30.00000030.009912SGR0418+5729archived Oct 6 2010 4:04PM  Nov 29 2010 6:10AM NRea
1250153313147ACIS-SNONE5.0000005.000000Crabarchived Oct 5 2010 4:26PM  Nov 28 2010 11:17AM Nferrigno
1250153213146ACIS-SNONE5.0000005.000000Crabarchived Oct 5 2010 4:26PM  Oct 28 2010 5:58PM Nferrigno
1150153113139ACIS-SNONE5.0000005.000000CrabNebulaarchived Sep 23 2010 3:29PM  Sep 28 2010 5:21AM NWeisskopf
1140128113122ACIS-SNONE10.00000010.026400ESO243-49HLX-1archived Sep 1 2010 9:49AM  Sep 6 2010 10:40PM DFarrell
1140114512314ACIS-SHETG6.0000006.000000CygX-1archived Jul 14 2010 10:31AM  Jul 24 2010 5:38PM NMcClintock
1140114412313ACIS-SHETG6.0000006.070000CygX-1archived Jul 14 2010 10:31AM  Jul 22 2010 4:39PM NMcClintock
1150137112312ACIS-SNONE30.00000030.009198SGR0418+5729archived Jul 12 2010 10:28AM  Jul 23 2010 3:16PM NRea
1140114112235ACIS-SHETG20.00000020.079600CirX-1archived Jun 29 2010 5:24PM  Jul 4 2010 5:22AM ND'A
0990093912234ACIS-INONE53.00000049.800438ChandraDeepField-Sarchived Jun 25 2010 4:49PM  Jul 22 2010 8:13PM 4Tananbaum
0990093912233ACIS-INONE35.00000036.043659ChandraDeepField-Sarchived Jun 25 2010 4:48PM  Jul 16 2010 10:52AM 4Tananbaum
0990093912232ACIS-INONE34.00000033.329777ChandraDeepField-Sarchived Jun 25 2010 4:45PM  Jul 18 2010 8:09PM 4Tananbaum
0990093912231ACIS-INONE25.00000025.047959ChandraDeepField-Sarchived Jun 23 2010 11:40AM  Jul 12 2010 3:49AM 4Tananbaum
0990093912230ACIS-INONE38.00000034.254918ChandraDeepField-Sarchived Jun 20 2010 2:29PM  Jul 11 2010 4:18AM 4Tananbaum
1150136912229ACIS-SNONE15.00000015.037309GRB100615Aarchived Jun 16 2010 3:07PM  Jun 21 2010 3:52AM NLevan
0990093912227ACIS-INONE55.00000055.043411ChandraDeepField-Sarchived Jun 10 2010 12:06PM  Jul 14 2010 9:28PM 4Tananbaum
0990093812223ACIS-INONE102.000000102.041441ChandraDeepField-Sarchived May 26 2010 4:55PM  Jun 13 2010 1:21AM 4Tananbaum
0990093812222ACIS-INONE31.00000031.049146ChandraDeepField-Sarchived May 26 2010 4:10PM  Jun 5 2010 3:09AM 4Tananbaum
1150136812221ACIS-SNONE10.00000010.065300XTEJ1810-197archived May 21 2010 11:36AM  Jun 7 2010 3:29AM DBernardini
0990093812220ACIS-INONE48.90000048.768154ChandraDeepField-Sarchived May 18 2010 8:29AM  Jun 18 2010 1:16PM 4Tananbaum
0990093812219ACIS-INONE34.20000034.106014ChandraDeepField-Sarchived May 18 2010 8:20AM  Jun 6 2010 4:49PM 4Tananbaum
0990093812218ACIS-INONE89.20000089.142158ChandraDeepField-Sarchived May 12 2010 5:03PM  Jun 11 2010 10:33AM 4Tananbaum
0990093612213ACIS-INONE62.10000062.098441ChandraDeepField-Sarchived Apr 28 2010 3:10PM  May 17 2010 2:55PM 4Tananbaum
1130028312203HRC-SLETG5.0000005.181632KTEriarchived Apr 9 2010 2:19PM  Apr 21 2010 11:03AM NDrake
0990093712138ACIS-INONE39.00000039.044418ChandraDeepField-Sarchived Mar 30 2010 8:19AM  Apr 18 2010 1:16PM 4Tananbaum
0990093712137ACIS-INONE94.00000094.010314ChandraDeepField-Sarchived Mar 30 2010 8:19AM  Apr 16 2010 9:10AM 4Tananbaum
0990093712135ACIS-INONE63.40000063.357678ChandraDeepField-Sarchived Mar 25 2010 3:35PM  Apr 6 2010 9:50AM 4Tananbaum
0990093712129ACIS-INONE78.20000078.160096ChandraDeepField-Sarchived Mar 17 2010 10:54AM  Apr 3 2010 3:40PM 4Tananbaum
0990093612128ACIS-INONE23.10000023.104259ChandraDeepField-Sarchived Mar 9 2010 4:02PM  Mar 27 2010 1:28PM 4Tananbaum
1140113812127ACIS-SHETG25.00000023.1677504U1608-52archived Mar 8 2010 4:25PM  Mar 15 2010 4:46AM NOzel
0990093612123ACIS-INONE25.10000025.118041ChandraDeepField-Sarchived Mar 4 2010 3:45PM  Mar 21 2010 8:23AM 4Tananbaum
1130027712102HRC-SLETG25.00000023.244182UScorpiiarchived Jan 28 2010 12:11PM  Feb 14 2010 11:56AM NOrio
1130027612101HRC-SLETG5.0000005.158825KTEriarchived Jan 26 2010 9:26AM  Feb 6 2010 6:43AM NDrake
1130027512100HRC-SLETG5.0000005.181375KTEriarchived Jan 26 2010 9:26AM  Jan 31 2010 10:43PM NDrake
1130027412097HRC-SLETG15.00000015.183582KTEriarchived Jan 20 2010 12:33PM  Jan 23 2010 10:01PM NNess
1170231712087ACIS-SNONE3.0000003.061700Q0957+561archived Dec 22 2009 2:14PM  Jun 23 2010 11:29PM NGoicoechea
1170231612086ACIS-SNONE3.0000003.062981Q0957+561archived Dec 22 2009 2:13PM  Jun 10 2010 10:14AM NGoicoechea
1170231512085ACIS-SNONE3.0000003.061700Q0957+561archived Dec 22 2009 2:13PM  May 25 2010 11:08PM NGoicoechea
1170231412084ACIS-SNONE3.0000003.182400Q0957+561archived Dec 22 2009 2:13PM  May 15 2010 4:53AM NGoicoechea
1170231312083ACIS-SNONE3.0000003.151800Q0957+561archived Dec 22 2009 2:12PM  Apr 27 2010 1:21PM NGoicoechea
1170231212082ACIS-SNONE3.0000003.182400Q0957+561archived Dec 22 2009 2:12PM  Apr 13 2010 1:14PM NGoicoechea
1170231112081ACIS-SNONE3.0000003.170500Q0957+561archived Dec 22 2009 2:11PM  Mar 29 2010 9:43PM NGoicoechea
1170231012080ACIS-SNONE3.0000003.126300Q0957+561archived Dec 22 2009 2:11PM  Mar 15 2010 12:00PM NGoicoechea
1170230912079ACIS-SNONE3.0000003.150100Q0957+561archived Dec 22 2009 2:11PM  Mar 3 2010 2:58PM NGoicoechea
1170230812078ACIS-SNONE3.0000003.182400Q0957+561archived Dec 22 2009 2:10PM  Feb 18 2010 6:43AM NGoicoechea
1170230712077ACIS-SNONE3.0000003.185800Q0957+561archived Dec 22 2009 2:10PM  Feb 1 2010 12:50AM NGoicoechea
1170230612076ACIS-SNONE3.0000003.060000Q0957+561archived Dec 22 2009 1:57PM  Jan 17 2010 12:56PM NGoicoechea
1040113712067ACIS-SHETG11.00000011.0812501A0535+262archived Dec 15 2009 1:14PM  Dec 31 2009 2:19AM Dreynolds
1040113712066ACIS-SHETG9.0000008.9172501A0535+262archived Dec 10 2009 2:59AM  Dec 28 2009 11:08AM Dreynolds
0990093612055ACIS-INONE81.80000081.749978ChandraDeepField-Sarchived Nov 24 2009 3:21PM  May 15 2010 5:35PM 4Tananbaum
0990093912054ACIS-INONE62.00000061.810778ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Jul 9 2010 12:02PM 4Tananbaum
0990093912053ACIS-INONE75.00000069.009060ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Jul 5 2010 3:30AM 4Tananbaum
0990093912052ACIS-INONE112.600000111.875500ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Jun 15 2010 4:32PM 4Tananbaum
0990093812051ACIS-INONE58.00000058.044247ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Jun 10 2010 11:57AM 4Tananbaum
0990093812050ACIS-INONE30.00000030.048259ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Jun 3 2010 7:03AM 4Tananbaum
0990093812049ACIS-INONE88.00000088.088925ChandraDeepField-Sarchived Nov 24 2009 3:21PM  May 28 2010 7:18PM 4Tananbaum
0990093712048ACIS-INONE140.000000139.932947ChandraDeepField-Sarchived Nov 24 2009 3:21PM  May 23 2010 7:26AM 4Tananbaum
0990093712047ACIS-INONE10.30000010.276459ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Apr 12 2010 1:47PM 4Tananbaum
0990093712046ACIS-INONE79.00000079.056119ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Apr 8 2010 8:31AM 4Tananbaum
0990093712045ACIS-INONE101.000000101.037949ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Mar 28 2010 4:58PM 4Tananbaum
0990093612044ACIS-INONE100.800000100.842837ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Mar 23 2010 11:55AM 4Tananbaum
0990093612043ACIS-INONE131.300000131.294013ChandraDeepField-Sarchived Nov 24 2009 3:21PM  Mar 18 2010 1:58AM 4Tananbaum
1020065612009ACIS-SNONE25.00000024.473600V838Monarchived Oct 13 2009 10:58AM  Jan 12 2010 8:44AM NKastner
1040112511803HRC-INONE10.00000010.156982ESO243-49HLX-1archived Aug 10 2009 5:46PM  Aug 17 2009 12:41PM NFarrell
1040112411802ACIS-SNONE5.0000005.035200NGC6440X-2archived Aug 4 2009 6:03PM  Aug 10 2009 8:26AM NHeinke
1050117410929ACIS-INONE20.00000020.134400PSRJ1622-49archived Jul 8 2009 9:03AM  Jul 10 2009 7:43AM 3Rea
1070197310921ACIS-SNONE5.0000005.0464002XMMJ130200.1+27465archived Jun 3 2009 12:08PM  Jun 27 2009 3:28AM NWatson
1040106610919HRC-INONE1.0000001.175675ESO243-49HLX-1archived May 29 2009 1:38PM  Jul 4 2009 2:15PM NFarrell
1040106510907ACIS-SNONE20.00000018.448100GROJ1655-40archived Apr 17 2009 5:40PM  Jun 8 2009 2:46AM NGallo
0920056910845ACIS-SNONE40.00000040.134400ZCMaarchived Dec 18 2008 11:19AM  Dec 28 2008 10:48PM NStelzer
0920056810826HRC-INONE5.0000004.97842551Pegarchived Nov 17 2008 8:51AM  Dec 6 2008 12:52PM NSchmitt
0920056810825ACIS-SNONE5.0000004.98240051Pegarchived Nov 17 2008 8:45AM  Dec 6 2008 11:21AM NSchmitt
0940105110574HRC-INONE5.0000005.162669XTEJ1701-407archived Aug 18 2008 3:29PM  Aug 26 2008 8:24PM DKaplan
0950115210573ACIS-SNONE10.00000010.152500GRB080307archived Aug 14 2008 5:07PM  Sep 22 2008 8:36AM NPage
0940105010571HRC-INONE1.0000001.183875VPuppisarchived Aug 7 2008 2:56PM  Sep 1 2008 1:40AM NMaccarone
094009349883ACIS-SNONE10.00000010.198400XMMUJ005510.7-37385archived Jun 25 2008 2:22AM  Jul 8 2008 9:26PM NKong
094009339882ACIS-SNONE30.00000030.180000AXJ1754.2-2754archived Jun 24 2008 3:23PM  Jul 15 2008 12:30AM DKeek
095010189862ACIS-SNONE30.00000030.147200SHB080503archived May 16 2008 4:13PM  May 25 2008 6:28PM NButler
095010179853ACIS-SNONE30.00000030.175400SHB080503archived May 5 2008 9:16PM  May 7 2008 7:35PM NButler
094009329850HRC-INONE2.0000002.186069XTEJ1719-291archived Apr 15 2008 8:53AM  Apr 27 2008 6:34PM DSala
097017719814ACIS-SNONE10.0000009.907200SDSSJ0952+2143archived Jan 23 2008 8:44AM  Feb 5 2008 4:43PM NKomossa
094009319805ACIS-SNONE5.0000005.175000m81-ot071213archived Dec 19 2007 2:43PM  Dec 21 2007 6:54PM DJonker
095010149799ACIS-SNONE21.50000021.569800SN2007onarchived Dec 12 2007 3:41PM  Dec 27 2007 1:35AM DRoelofs
095010149798ACIS-SNONE18.50000018.544200SN2007onarchived Dec 5 2007 3:21PM  Dec 24 2007 11:15AM DRoelofs
092005269769ACIS-INONE30.00000030.150559NGC2264field1archived Nov 9 2007 4:15PM  Mar 28 2008 3:02PM NMicela
092005269768ACIS-INONE30.00000028.154200NGC2264field1archived Nov 9 2007 4:08PM  Mar 12 2008 6:10PM NMicela
081000719763ACIS-SNONE10.00000010.17920017P/Holmesarchived Oct 29 2007 1:32PM  Oct 31 2007 4:21PM NDennerl
081000719762ACIS-SNONE10.00000010.18880017P/Holmesarchived Oct 29 2007 1:32PM  Oct 31 2007 1:26PM NDennerl
081000719755ACIS-SNONE10.00000010.13760017P/Holmesarchived Oct 26 2007 4:43PM  Oct 31 2007 10:31AM NDennerl
089007379718ACIS-INONE51.00000050.030737ChandraDeepField-Sarchived Sep 19 2007 3:00PM  Oct 3 2007 2:12PM NTananbaum
089007379596ACIS-INONE115.400000113.372872ChandraDeepField-Sarchived Sep 10 2007 3:32PM  Nov 4 2007 4:30AM NTananbaum
089007379593ACIS-INONE48.00000047.045600ChandraDeepField-Sarchived Sep 5 2007 12:11PM  Sep 22 2007 8:49PM NTananbaum
084009289584HRC-INONE2.0000002.184531M15archived Aug 27 2007 11:51AM  Sep 5 2007 3:23PM NHeinke
085010099579ACIS-INONE20.00000019.709759SN2007grarchived Aug 21 2007 1:16PM  Aug 29 2007 1:52AM NSoderberg
089007379578ACIS-INONE40.00000039.084800ChandraDeepField-Sarchived Aug 20 2007 4:20PM  Oct 30 2007 10:53PM NTananbaum
089007379575ACIS-INONE112.400000110.133372ChandraDeepField-Sarchived Aug 20 2007 4:18PM  Oct 27 2007 6:09AM NTananbaum
089007378597ACIS-INONE61.00000060.068618ChandraDeepField-Sarchived Aug 7 2007 3:31PM  Oct 17 2007 7:23AM NTananbaum
089007378596ACIS-INONE118.000000116.640477ChandraDeepField-Sarchived Aug 7 2007 3:31PM  Oct 24 2007 1:46PM NTananbaum
089007378595ACIS-INONE118.000000116.950436ChandraDeepField-Sarchived Aug 7 2007 3:31PM  Oct 19 2007 2:35PM NTananbaum
089007378594ACIS-INONE151.200000143.272414ChandraDeepField-Sarchived Aug 7 2007 3:31PM  Nov 1 2007 12:10PM NTananbaum
089007378593ACIS-INONE51.00000050.145559ChandraDeepField-Sarchived Aug 7 2007 3:31PM  Oct 6 2007 2:22AM NTananbaum
089007378592ACIS-INONE88.00000087.785596ChandraDeepField-Sarchived Aug 7 2007 3:31PM  Oct 22 2007 12:36PM NTananbaum
089007378591ACIS-INONE46.00000046.034877ChandraDeepField-Sarchived Aug 7 2007 3:31PM  Sep 20 2007 5:41AM NTananbaum
084006918564ACIS-INONE11.20000011.152000SWIFTJ1756.9-2508archived Jun 19 2007 12:29PM  Jul 6 2007 1:44AM NDiSalvo
084006908562ACIS-SHETG10.00000010.152500SwiftJ195509.6+2614archived Jun 12 2007 1:01PM  Jun 14 2007 6:17PM DKANBACH
084006898556HRC-INONE7.0000007.180382CirX-1archived Apr 27 2007 3:09PM  May 16 2007 9:11PM DJonker
084006888547HRC-INONE43.00000043.290108CirX-1archived Mar 30 2007 1:52PM  Apr 21 2007 5:32AM DJonker
086006498524ACIS-SNONE30.00000030.041600GRB070125archived Feb 22 2007 9:56AM  Mar 5 2007 9:49PM NFrail
085008228518ACIS-SNONE3.0000003.043200SN2005kdarchived Jan 30 2007 2:09PM  Mar 4 2007 2:54PM NPooley
087015838517ACIS-SNONE5.0000005.153200M87archived Jan 26 2007 3:19PM  Mar 22 2007 4:06AM NHarris
087015828516ACIS-SNONE5.0000005.159200M87archived Jan 26 2007 3:19PM  Mar 19 2007 10:38AM NHarris
087015818515ACIS-SNONE5.0000005.177600M87archived Jan 26 2007 3:19PM  Mar 14 2007 2:43PM NHarris
087015808514ACIS-SNONE5.0000004.929200M87archived Jan 26 2007 3:19PM  Mar 12 2007 11:52AM NHarris
087015798513ACIS-SNONE5.0000005.182800M87archived Jan 26 2007 3:19PM  Feb 24 2007 3:16AM NHarris
087015788512ACIS-SNONE5.0000005.185600M87archived Jan 26 2007 3:19PM  Feb 21 2007 11:58PM NHarris
087015778511ACIS-SNONE5.0000005.185600M87archived Jan 26 2007 3:19PM  Feb 18 2007 10:23PM NHarris
087015768510ACIS-SNONE5.0000005.183600M87archived Jan 26 2007 3:19PM  Feb 15 2007 9:37AM NHarris
085008218508HRC-INONE2.0000002.1599311RXSJ141256.0+79220archived Jan 19 2007 12:55PM  Feb 18 2007 6:05PM DRutledge
085008208506ACIS-SNONE20.00000020.182000CXOJ164710.2-455216archived Jan 8 2007 1:10PM  Feb 2 2007 7:26PM NWoods
075008178480HRC-INONE1.0000001.149025RBS1774(1RXSJ214303archived Nov 6 2006 2:27PM  Nov 26 2006 10:15PM DZane
072004608474ACIS-INONE10.0000009.753600L1415EXorarchived Oct 30 2006 11:32AM  Nov 18 2006 2:41AM NKastner
075008168473ACIS-SNONE30.00000030.124800SN2006gyarchived Oct 30 2006 11:20AM  Nov 14 2006 8:57PM NPooley
075008158457ACIS-SNONE10.0000009.961600SN2006jcarchived Oct 16 2006 12:14PM  Nov 4 2006 6:23AM NImmler
075008148455ACIS-SNONE15.00000015.186750CXOJ164710.2-455216archived Oct 12 2006 12:50PM  Oct 28 2006 7:19AM DKas
074006808273ACIS-INONE21.60000020.030359LSI+61303archived Sep 8 2006 3:29PM  Oct 25 2006 10:32PM NPerez-Torres
076006077373ACIS-SNONE7.0000007.184000XMMUJ132218.3-16424archived Jul 12 2006 5:56PM  Jul 31 2006 3:41AM NMiniutti
074005617335ACIS-SNONE10.0000009.376000PSRB1931+24archived May 5 2006 2:30PM  Jul 20 2006 3:01PM DRea
071000677334ACIS-SNONE4.0000004.18240073P/Schwassmann-Wacharchived May 2 2006 2:32PM  May 23 2006 10:34AM NWolk
071000667333ACIS-SNONE4.0000004.18240073P/Schwassmann-Wacharchived May 2 2006 2:32PM  May 23 2006 9:19AM NWolk
071000657332ACIS-SNONE4.0000004.18560073P/Schwassmann-Wacharchived May 2 2006 2:32PM  May 23 2006 8:03AM NWolk
071000647331ACIS-SNONE4.0000004.18560073P-B/Schwassmann-Waarchived May 2 2006 2:32PM  May 23 2006 6:48AM NWolk
071000637330ACIS-SNONE4.0000004.10560073P-B/Schwassmann-Waarchived May 2 2006 2:32PM  May 23 2006 5:33AM NWolk
073001797298HRC-SLETG20.00000020.126132RSOpharchived Mar 3 2006 1:28PM  Jun 4 2006 12:25PM NStarrfield
073001787297HRC-SLETG10.0000009.505082RSOpharchived Mar 3 2006 1:28PM  Apr 20 2006 5:43PM NStarrfield
073001777296HRC-SLETG10.00000010.152882RSOpharchived Mar 3 2006 1:28PM  Mar 24 2006 12:40PM NStarrfield
073001727280ACIS-SHETG10.00000010.075000RSOpharchived Feb 14 2006 11:50AM  Feb 26 2006 3:36PM NStarrfield
075006937277ACIS-SNONE15.00000014.998400SN2005kearchived Feb 7 2006 9:31AM  Feb 19 2006 11:11AM NImmler
075006927276HRC-INONE1.0000001.112125IGRJ15359-5750archived Feb 6 2006 12:40PM  Mar 28 2006 4:54AM NIsrael
075006917275HRC-INONE1.0000001.122631IGRJ18048-1544archived Feb 6 2006 12:40PM  Mar 28 2006 4:10AM NIsrael
075006907274HRC-INONE1.0000001.097006IGRJ17513-2011archived Feb 6 2006 12:40PM  Mar 28 2006 3:40AM NIsrael
075006897273HRC-INONE1.0000001.095981IGRJ17488-3253archived Feb 6 2006 12:40PM  Mar 28 2006 3:07AM NIsrael
074005597272HRC-INONE2.0000002.135331SWIFTJ1626.6-5156archived Feb 2 2006 3:13PM  Feb 21 2006 6:28AM NHoman
074005587269ACIS-SNONE1.0000001.161600HD109962archived Jan 23 2006 1:03PM  Feb 2 2006 2:14PM NWalter
065006857241ACIS-SNONE50.00000050.179190SN2005gjarchived Nov 29 2005 4:53PM  Dec 11 2005 5:26PM NPooley
058005557225ACIS-INONE2.0000002.045959MACS1720.3+3536archived Nov 9 2005 3:10PM  Nov 27 2005 3:12AM NAllen
063001717186ACIS-SHETG50.00000050.155000RTCruarchived Oct 5 2005 2:19PM  Oct 19 2005 10:41AM NSokoloski
062003726375HRC-INONE5.0000005.150881AlphaCentauriarchived Aug 31 2005 11:31AM  Dec 17 2006 4:58AM NAyres
062003716374HRC-INONE5.0000005.157031AlphaCentauriarchived Aug 31 2005 11:31AM  May 12 2006 6:31PM NAyres
062003706373HRC-INONE5.0000005.187781AlphaCentauriarchived Aug 31 2005 11:31AM  Oct 21 2005 2:59AM NAyres
064004726354ACIS-SNONE20.00000019.043960GRB050709archived Jul 19 2005 11:34AM  Jul 25 2005 9:03PM NFrail
064004706298HRC-INONE5.0000004.767531SAXJ1808.4-3658archived Jun 7 2005 9:38AM  Jun 20 2005 11:25PM NChakrabarty
064004696297ACIS-SHETG15.00000014.344000SAXJ1808.4-3658archived Jun 6 2005 3:27PM  Jun 12 2005 2:32AM NGalloway
065006036284ACIS-SNONE30.00000029.788040SN2005bxarchived May 6 2005 3:24PM  Jul 30 2005 11:11AM NFilippenko
067011806278ACIS-INONE3.5000003.638000IGRJ19473+4452archived Apr 20 2005 2:33PM  Jul 31 2005 9:32AM NSunyaev
067011796277ACIS-INONE3.5000003.759572IGRJ13091+1137archived Apr 20 2005 2:33PM  Jul 25 2005 10:25AM NSunyaev
067011786276ACIS-INONE3.5000003.260449IGRJ12391-1612archived Apr 20 2005 2:33PM  Jul 25 2005 11:45AM NSunyaev
067011776275ACIS-INONE3.5000003.260799IGRJ12026-5349archived Apr 20 2005 2:33PM  Jun 16 2005 6:10AM NSunyaev
067011766274ACIS-INONE3.5000003.676799IGRJ11085-5100archived Apr 20 2005 2:33PM  Jul 1 2005 3:58AM NSunyaev
067011756273ACIS-INONE3.5000003.707715IGRJ10252-6829archived Apr 20 2005 2:33PM  Jul 30 2005 9:24AM NSunyaev
067011746272ACIS-INONE3.5000003.257599IGRJ07563-4137archived Apr 20 2005 2:33PM  Jun 16 2005 4:46AM NSunyaev
067011736271ACIS-INONE3.5000003.459199IGRJ05007-7047archived Apr 20 2005 2:33PM  Jun 16 2005 3:25AM NSunyaev
065006016269ACIS-SNONE20.00000020.184090GRB050412archived Apr 14 2005 10:32AM  Apr 17 2005 9:43AM NBerger
064004686261ACIS-SNONE10.00000010.180800J1638-4725archived Mar 14 2005 10:52AM  May 4 2005 7:47PM NMcLaughlin
055006006260ACIS-SNONE10.00000010.140790GCRTJ1745-3009archived Mar 10 2005 3:52PM  May 1 2005 12:47AM DHyman
064004676259ACIS-SNONE5.0000005.169599HESSJ1826-148archived Mar 10 2005 3:26PM  Apr 13 2005 3:01AM NFunk
065005996251HRC-SNONE30.00000027.149430SGR1806-20archived Feb 22 2005 3:08PM  Apr 22 2005 7:03PM DKouveliotou
067011726227ACIS-SNONE10.00000010.323190NGC3690archived Feb 8 2005 11:54AM  Feb 14 2005 4:53AM NNandra
065005986224ACIS-INONE20.00000019.059190SGR1806-20archived Jan 27 2005 5:35PM  Feb 9 2005 7:25AM 1Fox
065005976207ACIS-SNONE30.00000029.100500SGR1806-20archived Jan 18 2005 10:13AM  Feb 8 2005 10:54PM 1Rea
062003636204ACIS-SNONE5.0000005.136400V1118Oriarchived Jan 18 2005 9:48AM  Jan 26 2005 3:24AM DAudard
064004476181ACIS-SNONE15.00000014.182800IGRJ00291+5934archived Dec 17 2004 5:25PM  Feb 6 2005 1:45PM NJonker
064004466180ACIS-SNONE10.0000009.894359IGRJ00291+5934archived Dec 17 2004 5:25PM  Jan 14 2005 12:11AM NJonker
064004456179ACIS-SNONE5.0000005.185200IGRJ00291+5934archived Dec 17 2004 5:25PM  Jan 1 2005 9:24PM NJonker
058005576172ACIS-INONE30.00000030.144270MACS1621.6+3810archived Nov 30 2004 9:54AM  Dec 25 2004 10:04PM NAllen
055005916129ACIS-INONE20.00000019.508000GRB040912archived Sep 13 2004 1:18PM  Sep 21 2004 11:18AM NRicker
055005906128ACIS-INONE20.00000018.168000GRB040912archived Sep 13 2004 1:18PM  Sep 15 2004 10:24PM NRicker
058005606112ACIS-INONE10.0000009.510799MACS1427.2+4407archived Aug 24 2004 2:41PM  Feb 12 2005 2:19AM NAllen
058005596111ACIS-INONE50.00000050.157877MACS0744.9+3927archived Aug 24 2004 2:41PM  Dec 3 2004 9:25PM NAllen
058005586110ACIS-INONE70.00000064.042810MACS1311.0-0311archived Aug 24 2004 2:41PM  Apr 20 2005 12:23AM NAllen
058005576109ACIS-INONE40.00000038.046250MACS1621.6+3810archived Aug 24 2004 2:41PM  Dec 11 2004 2:31PM NAllen
058005566108ACIS-INONE40.00000040.169750MACS0329.7-0212archived Aug 24 2004 2:41PM  Dec 6 2004 6:18AM NAllen
058005556107ACIS-INONE38.00000034.332410MACS1720.3+3536archived Aug 24 2004 2:41PM  Nov 22 2005 9:35PM NAllen
058005546106ACIS-INONE40.00000035.770890MACS0159.8-0849archived Aug 24 2004 2:41PM  Dec 4 2004 12:14PM NAllen
058005536105ACIS-INONE40.00000037.770350MACS0011.7-1523archived Aug 24 2004 2:41PM  Jun 28 2005 11:51AM NAllen
058005526104ACIS-INONE10.0000009.737000Abell2204archived Aug 24 2004 2:41PM  Sep 20 2004 11:42AM NAllen
058005516103ACIS-INONE10.00000010.406000PKS0745-191archived Aug 24 2004 2:41PM  Sep 24 2004 12:35AM NAllen
058005506102ACIS-INONE10.00000010.127000Abell478archived Aug 24 2004 2:41PM  Sep 13 2004 5:15PM NAllen
058005496101ACIS-INONE10.00000010.050190Abell2029archived Aug 24 2004 2:41PM  Dec 17 2004 3:50AM NAllen
055005856098ACIS-INONE5.0000004.707000VHEJ1303-63archived Aug 18 2004 9:57AM  Sep 25 2004 6:02PM DHalpern
055005085365ACIS-SNONE10.00000010.163000GRB040812archived Aug 13 2004 12:06PM  Aug 22 2004 10:12AM NKouveliotou
055005075364ACIS-SNONE10.00000010.175000GRB040812archived Aug 13 2004 12:06PM  Aug 17 2004 7:28AM NKouveliotou
056004125360ACIS-INONE5.0000005.174000CXOGCJ174540.0-2900archived Aug 3 2004 5:00PM  Aug 28 2004 12:21PM NBaganoff
041000525352HRC-INONE4.7000004.657000Moonarchived Jul 13 2004 3:11PM  Jul 28 2004 1:30AM NDrake
041000525351HRC-INONE5.6000005.471000Moonarchived Jul 13 2004 3:11PM  Jul 27 2004 11:13PM NDrake
041000525327HRC-INONE5.6000005.638000Moonarchived May 12 2004 1:59PM  Jun 2 2004 10:58AM NDrake
051000535326ACIS-SNONE3.3000003.471000C/2001Q4(NEAT)archived May 3 2004 2:15PM  May 12 2004 8:58PM DLisse
051000535325ACIS-SNONE3.3000003.484000C/2001Q4(NEAT)archived May 3 2004 2:14PM  May 12 2004 7:55PM DLisse
041000525324HRC-INONE5.6400005.772000Moonarchived Apr 23 2004 2:22PM  May 4 2004 7:00AM NDrake
051000535321ACIS-SNONE3.4000003.558000C/2001Q4(NEAT)archived Apr 16 2004 2:05PM  May 12 2004 6:50PM DLisse
055005065314ACIS-SNONE30.00000030.156000GRB031203archived Mar 17 2004 5:29PM  Apr 18 2004 11:59AM DKouveliotou
041000525312HRC-INONE5.6000005.679000Moonarchived Mar 15 2004 2:11PM  Jun 2 2004 8:41AM NDrake
041000525311HRC-INONE5.6400005.521000Moonarchived Mar 15 2004 2:05PM  May 4 2004 4:36AM NDrake
052002985308ACIS-SNONE5.0000004.963000IRAS05436-0007archived Feb 19 2004 6:43PM  Mar 22 2004 12:35AM NKastner
052002975307ACIS-SNONE5.0000005.561000IRAS05436-0007archived Feb 19 2004 6:43PM  Mar 7 2004 1:41AM NKastner
055005055306ACIS-SNONE15.00000014.758000SN2001emarchived Feb 9 2004 3:39PM  Apr 4 2004 7:41PM NPooley
055005045305HRC-SLETG35.00000035.705000RXJ0720-3125archived Feb 9 2004 3:38PM  Feb 27 2004 4:53AM NVink
057010145302ACIS-SNONE30.00000031.121000NGC4395archived Jan 30 2004 8:22AM  Apr 11 2004 1:28AM NMoran
057010135301ACIS-SNONE30.00000029.730000NGC4395archived Jan 30 2004 8:22AM  Apr 10 2004 3:06AM NMoran
055005035298ACIS-SNONE25.00000021.848000GRB031203archived Jan 13 2004 11:16AM  Jan 22 2004 9:34PM NKulkarni
053001455293HRC-SLETG40.00000041.953000MiraABarchived Dec 19 2003 11:52AM  Jan 11 2004 2:09PM DKarovska
053001445292HRC-SLETG10.00000010.308000V4743Sgrarchived Dec 18 2003 5:07PM  Feb 28 2004 1:31AM NStarrfield
054003765291ACIS-SNONE10.00000010.137000PSRJ0737-3039archived Dec 18 2003 4:54PM  Jan 18 2004 7:56PM 1McLaughlin
045005005247HRC-INONE5.0000004.871000IGRJ16316-4028archived Oct 31 2003 1:24PM  Jan 18 2004 1:07PM DFoschini
045004995246ACIS-SNONE25.00000025.509000SN2003jdarchived Oct 31 2003 1:20PM  Nov 10 2003 7:08PM NWatson
045004985240HRC-INONE3.0000002.884000XTEJ1810-197archived Oct 9 2003 2:54PM  Nov 1 2003 3:26PM NIsrael
045004154454HRC-INONE3.0000002.833000XTEJ1810-197archived Aug 12 2003 2:22PM  Aug 27 2003 10:43PM NGotthelf
045004134449ACIS-SNONE20.00000018.435000SN2002icarchived Aug 4 2003 2:52PM  Aug 11 2003 9:40PM DHughes
045004124443ACIS-SNONE25.00000025.125000SGR1806-20archived Jul 21 2003 6:54PM  Aug 3 2003 12:13PM DWoods
044003244439ACIS-SHETG10.0000009.987000XTEJ1814-338archived Jun 6 2003 4:18PM  Jun 20 2003 2:12AM DChakrabarty
048003754438ACIS-SNONE30.00000029.136000RCS0439.6-2905archived May 12 2003 2:31PM  Jun 6 2003 6:17AM DBautz
044003234434ACIS-SNONE47.00000047.051000IGRJ16358-4726archived Apr 10 2003 4:23PM  Apr 21 2003 3:49AM DKouveliotou
045004114432ACIS-SLETG100.00000098.100000H2650archived Mar 28 2003 10:14AM  Mar 29 2003 3:05AM NRicker
044003224426HRC-SNONE3.0000002.824000XTEJ1807-294archived Feb 27 2003 3:35PM  Mar 10 2003 8:34AM DMARKWARDT
045004104425ACIS-SNONE40.00000040.172000GRB030226archived Feb 26 2003 3:15PM  Feb 27 2003 5:14PM NPedersen
044003214424ACIS-SNONE10.00000010.687000XTEJ1908+094archived Feb 20 2003 2:41PM  May 14 2003 1:51AM DJonker
044003204423ACIS-SNONE5.0000005.150000XTEJ1908+094archived Feb 20 2003 2:41PM  Apr 19 2003 3:14PM DJonker
044003194422ACIS-SNONE5.0000005.212000XTEJ1908+094archived Feb 20 2003 2:41PM  Mar 24 2003 12:07AM DJonker
044003184420ACIS-SHETG75.00000076.220000GX339-4archived Feb 12 2003 1:59PM  Mar 17 2003 8:05PM DMiller
045004094417ACIS-SNONE30.00000030.415000SN2003Larchived Jan 30 2003 7:05PM  Feb 10 2003 3:59AM NKulkarni
031000384410HRC-INONE1.0000001.116000EARTHarchived Dec 4 2002 4:43PM  Feb 7 2003 1:23AM DGladstone
035004084409ACIS-SNONE30.00000030.431000GRB021004archived Nov 17 2002 12:28PM  Nov 25 2002 5:51PM NSako
035004074405ACIS-SNONE10.00000010.115000SN2002HIarchived Nov 7 2002 8:46PM  Dec 10 2002 5:45PM NLewin
035004064404ACIS-SNONE30.00000030.335000SN2002HHarchived Nov 7 2002 8:42PM  Nov 25 2002 8:58AM NLewin
035004054381ACIS-SHETG80.00000088.130000GRB021004archived Oct 4 2002 12:41PM  Oct 5 2002 8:58AM NHarrison
035004044364ACIS-SHETG80.00000078.122000GRB020813archived Aug 13 2002 5:56AM  Aug 13 2002 11:46PM NRicker
036003304360ACIS-INONE5.0000004.969000M31archived Aug 2 2002 9:52AM  Aug 11 2002 6:15PM NPrimini
034003164358ACIS-INONE5.0000004.979000TEVJ2032+4130archived Aug 1 2002 5:35PM  Aug 11 2002 8:07PM DButt
034003154285ACIS-SNONE5.0000004.687000V4641SGRarchived Jul 19 2002 11:42AM  Aug 5 2002 4:16AM DRupen
034002703724ACIS-SHETG30.00000026.400000CYGX-1archived Jul 15 2002 12:33PM  Jul 30 2002 5:42PM NFeng
034002683672ACIS-SNONE20.00000018.255000XTEJ1550-564archived May 29 2002 9:42AM  Jun 19 2002 9:17AM DCorbel
034002673671ACIS-SNONE5.0000005.5380001E1740.7-2942archived May 29 2002 9:33AM  Aug 17 2002 1:24PM DHeindl
034002663670ACIS-SHETG10.00000010.1400001E1740.7-2942archived May 29 2002 9:33AM  Jun 13 2002 7:29PM DHeindl
034002653661ACIS-SLETG20.00000017.961000XTEJ0929-314archived May 10 2002 3:51PM  May 15 2002 12:43AM DChakrabarty
035002983496ACIS-SNONE25.00000024.188000SN2001IGarchived Apr 30 2002 12:59PM  Jun 11 2002 6:20AM NSchlegel
035002973495ACIS-SNONE25.00000023.734000SN2001IGarchived Apr 30 2002 12:59PM  May 21 2002 11:53PM NSchlegel
035002963494ACIS-SNONE15.00000014.755000XRF020427archived Apr 29 2002 3:42PM  May 14 2002 3:55AM NFox
035002953493ACIS-SNONE15.00000013.916000XRF020427archived Apr 29 2002 3:42PM  May 6 2002 5:46AM NFox
034002473492ACIS-SNONE5.0000005.231000RXJ170930.2-263927archived Apr 22 2002 3:15PM  Apr 23 2002 9:58PM DJonker
034002563490ACIS-SNONE7.0000007.648000AQLX-1archived Apr 5 2002 12:13PM  Sep 3 2002 4:27PM DRutledge
034002553489ACIS-SNONE7.0000007.858000AQLX-1archived Apr 5 2002 12:13PM  Aug 18 2002 8:19AM DRutledge
034002543488ACIS-SNONE7.0000007.172000AQLX-1archived Apr 5 2002 12:13PM  Jul 22 2002 9:01PM DRutledge
034002533487ACIS-SNONE7.0000006.549000AQLX-1archived Apr 5 2002 12:13PM  Jul 5 2002 3:45PM DRutledge
034002523486ACIS-SNONE7.0000007.151000AQLX-1archived Apr 5 2002 12:13PM  Jun 11 2002 3:50AM DRutledge
034002513485ACIS-SNONE7.0000007.672000AQLX-1archived Apr 5 2002 12:13PM  May 20 2002 7:41AM DRutledge
034002503484ACIS-SNONE7.0000007.160000AQLX-1archived Apr 5 2002 12:13PM  May 4 2002 11:04PM DRutledge
034002493483HRC-SNONE3.0000002.976000XTEJ1751-305archived Apr 5 2002 10:44AM  Apr 10 2002 4:31PM DMARKWARDT
034002483481ACIS-SNONE1.0000001.133000XTEJ1908+094archived Apr 3 2002 2:33PM  Apr 15 2002 5:39AM NRupen
035002943477ACIS-SNONE20.00000020.057000GRB020321archived Mar 25 2002 11:28AM  Mar 31 2002 2:13AM NFox
034002463475ACIS-SNONE5.0000005.965000RXJ170930.2-263927archived Mar 19 2002 3:24PM  Apr 10 2002 5:49PM DJonker
034002393464ACIS-SNONE5.0000005.147000RXJ170930.2-263927archived Mar 11 2002 9:44AM  Apr 1 2002 12:43AM DJonker
034002383463ACIS-SNONE8.4770008.477000RXJ170930.2-263927archived Mar 11 2002 9:44AM  Mar 18 2002 11:46AM DJonker
034002373462ACIS-SNONE15.00000014.210000RXJ170930.2-263927archived Mar 11 2002 9:44AM  Mar 12 2002 1:52PM DJonker
033000903455ACIS-SHETG35.00000034.457000GKPERarchived Mar 6 2002 5:15PM  Apr 9 2002 3:06PM DMauche
033000893454ACIS-SHETG35.00000032.102000GKPERarchived Mar 6 2002 5:15PM  Mar 27 2002 9:49AM DMauche
031000343453ACIS-SNONE12.00000011.964000C/2002C1archived Mar 6 2002 2:20PM  Apr 15 2002 11:15PM DDennerl
035002923449ACIS-SNONE3.0000002.662000SGR1900+14archived Feb 27 2002 4:34PM  Mar 11 2002 11:03AM DWoods
034002363448ACIS-SNONE30.00000027.457000XTEJ1550-564archived Feb 14 2002 12:00PM  Mar 11 2002 3:16PM DCorbel
031000343447ACIS-SNONE12.00000011.718000C/2002C1archived Feb 14 2002 9:25AM  Apr 15 2002 1:52AM DDennerl
035002913441ACIS-INONE15.00000014.672000XRF011130archived Feb 4 2002 5:21PM  Feb 20 2002 10:18AM NRicker
035002873437ACIS-INONE10.00000010.064000GRB020127archived Jan 30 2002 1:31PM  Feb 11 2002 11:17AM NFox
035002863436ACIS-INONE10.0000009.968000GRB020127archived Jan 30 2002 1:31PM  Jan 31 2002 10:37PM NFox
033000873434ACIS-SNONE5.0000005.629000IMNORMAEarchived Jan 23 2002 12:58PM  Feb 4 2002 6:01PM NStarrfield
037006123419ACIS-SNONE100.00000097.944000MGJ0414+0534archived Dec 7 2001 4:55PM  Jan 9 2002 12:00AM DChartas
031000323412ACIS-SNONE20.00000020.122000FXRT011030archived Nov 15 2001 3:17PM  Nov 29 2001 11:09AM DHarrison
031000313411ACIS-SNONE50.00000047.209000FXRT011030archived Nov 9 2001 12:48AM  Nov 9 2001 5:44PM NHarrison
024002343407ACIS-SHETG30.00000030.070000CYGX-1archived Oct 19 2001 10:35AM  Oct 28 2001 4:33PM DCui
025002853399HRC-SLETG9.5000009.318000RXJ1856.5-3754archived Oct 1 2001 9:20AM  Oct 15 2001 11:59AM NTananbaum
027006083395ACIS-SNONE30.00000028.777000MGJ0414+0534archived Sep 27 2001 10:49AM  Nov 9 2001 8:34AM DChartas
025002853382HRC-SLETG100.500000101.926000RXJ1856.5-3754archived Sep 18 2001 4:46PM  Oct 8 2001 8:31AM NTananbaum
025002853381HRC-SLETG170.000000171.073000RXJ1856.5-3754archived Sep 18 2001 4:46PM  Oct 12 2001 7:31PM NTananbaum
025002853380HRC-SLETG170.000000167.446000RXJ1856.5-3754archived Sep 18 2001 4:43PM  Oct 10 2001 5:18AM NTananbaum
024002333360ACIS-SNONE2.5000002.641000NGC6440archived Aug 15 2001 12:28PM  Aug 18 2001 8:23PM Nin'tZand
027006073359ACIS-SNONE6.0000005.760000SDSSPJ083643+005453archived Aug 10 2001 4:26PM  Jan 29 2002 12:02PM NBrandt
027006063358ACIS-SNONE8.0000008.262000SDSSPJ130608+035626archived Aug 10 2001 4:26PM  Jan 29 2002 6:28AM NBrandt
027006053357ACIS-SNONE8.0000008.057000SDSSPJ103027+052455archived Aug 10 2001 2:46PM  Jan 29 2002 9:11AM NBrandt
023000672514ACIS-SNONE10.00000010.179000WZSGEarchived Jul 31 2001 1:15PM  Sep 19 2001 1:56AM NKuulkers
023000662513ACIS-SNONE10.00000012.075000WZSGEarchived Jul 31 2001 1:15PM  Aug 22 2001 8:41AM NKuulkers
023000652512ACIS-SNONE5.0000004.910000WZSGEarchived Jul 31 2001 1:15PM  Aug 7 2001 5:47PM NKuulkers
023000612508ACIS-SNONE5.0000005.159000WZSGEarchived Jul 24 2001 6:25PM  Jul 29 2001 4:49PM NWheatley
023000592506HRC-SLETG20.00000019.984000WZSGEarchived Jul 24 2001 6:14PM  Aug 18 2001 8:07AM NWheatley
023000582505HRC-SLETG20.00000018.760000WZSGEarchived Jul 24 2001 6:14PM  Aug 6 2001 7:53PM NWheatley
023000572504HRC-SLETG20.00000019.950000WZSGEarchived Jul 24 2001 6:14PM  Jul 27 2001 2:44AM NWheatley
023000562492ACIS-SNONE20.00000019.885000CIAQLarchived Jul 6 2001 4:17PM  Aug 1 2001 12:52PM DGreiner
023000542465ACIS-SNONE2.0000002.149000CIAQLarchived May 9 2001 12:29PM  Jun 1 2001 8:41PM DGreiner
025002002459ACIS-SNONE20.00000018.896000SGR1900+14archived Apr 19 2001 11:22AM  Apr 30 2001 11:27PM NKouveliotou
025001992458ACIS-SNONE20.00000020.835000SGR1900+14archived Apr 18 2001 7:19PM  Apr 22 2001 4:58AM NKulkarni
027003932454ACIS-SNONE5.0000004.500000CIRCINUSGALAXYarchived Apr 13 2001 1:53PM  May 2 2001 4:20PM NMatt
024001642430HRC-INONE10.0000009.889000GRS1758-258archived Mar 9 2001 12:43PM  Mar 24 2001 7:43AM DHeindl
024001632429ACIS-SHETG30.00000030.280000GRS1758-258archived Mar 9 2001 12:43PM  Mar 24 2001 10:58AM DHeindl
024001622428ACIS-SNONE20.00000020.400000KS1731-260archived Mar 7 2001 3:25PM  Mar 27 2001 12:34AM DWijnands
028001782427ACIS-SNONE20.00000018.094000PKS0745-191archived Mar 7 2001 10:46AM  Jun 16 2001 5:50AM DFabian
025001972424ACIS-SNONE30.00000029.923000GRB010222archived Feb 22 2001 10:36AM  Feb 22 2001 10:28PM DPiro
024001612415ACIS-SHETG30.00000030.146000CYGNUSX-1archived Dec 16 2000 3:51PM  Jan 4 2001 6:20AM DMiller
029000662409ACIS-INONE69.00000069.895000CDFSarchived Dec 5 2000 4:47PM  Dec 19 2000 4:12AM NGIACCONI
029000662406ACIS-INONE31.00000030.079000CDFSarchived Dec 1 2000 2:25PM  Dec 10 2000 11:51PM NGIACCONI
022001252338ACIS-SHETG25.00000024.838000WR140archived Oct 27 2000 10:51AM  May 8 2001 8:01PM DPollock
022001242337ACIS-SHETG50.00000046.124000WR140archived Oct 27 2000 10:51AM  Dec 29 2000 10:32AM DPollock
013000532336ACIS-SHETG20.00000019.222000ZANDROMEDAEarchived Oct 26 2000 3:36PM  Nov 13 2000 3:19PM DCharles
029000662313ACIS-INONE132.000000132.115000CDFSarchived Sep 22 2000 10:04AM  Dec 21 2000 2:28AM NGIACCONI
029000662312ACIS-INONE136.000000125.323000CDFSarchived Sep 22 2000 10:04AM  Dec 13 2000 3:47AM NGIACCONI
029000662239ACIS-INONE132.000000132.469000CDFSarchived Aug 28 2000 4:08PM  Dec 23 2000 5:49PM NGIACCONI
014001121846ACIS-SNONE5.0000004.630000XTEJ1550-564archived Aug 7 2000 3:27PM  Sep 11 2000 5:10AM DTomsick
014001111845ACIS-SNONE5.0000005.164000XTEJ1550-564archived Aug 7 2000 3:27PM  Aug 21 2000 9:08AM DTomsick
017002661715HRC-SLETG20.00000019.839000MRK421archived May 8 2000 5:01PM  May 29 2000 5:53PM NFruscione
017002651714ACIS-SHETG20.00000019.830000MRK421archived May 8 2000 5:01PM  May 29 2000 11:57AM NFruscione
013000411706ACIS-SHETG60.00000059.881000EXHYAarchived Apr 13 2000 3:23PM  May 18 2000 9:59AM DHowell
014001101701ACIS-SLETG30.00000027.830000XTEJ1118+48archived Apr 7 2000 3:32PM  Apr 18 2000 6:36PM DMcClintock
01700202442ACIS-SNONE5.0000004.976000NGC526Aarchived Mar 16 2000 9:26AM  Apr 23 2000 6:54AM SWilson
01400093426ACIS-SHETG20.00000018.318000CYGX-3archived Feb 16 2000 2:09PM  Apr 6 2000 8:17PM NMcCollough
01400092425ACIS-SHETG20.00000021.533000CYGX-3archived Feb 16 2000 2:09PM  Apr 4 2000 2:05PM NMcCollough
01300037327ACIS-SNONE5.0000004.947000Mispointingarchived Jan 20 2000 10:10AM  Feb 8 2000 4:18PM DDiStefano
01500093364HRC-INONE50.00000048.159000PSRB0833-45archived Jan 19 2000 11:30AM  Feb 21 2000 2:11AM NHelfand
01300037327ACIS-SNONE5.0000004.947000Mispointingarchived Jan 19 2000 11:30AM  Feb 8 2000 4:18PM DDiStefano
015704701520ACIS-SNONE25.00000024.035000NGC3184archived Jan 19 2000 11:21AM  Feb 3 2000 11:00AM 3Schlegel
011000111465HRC-SLETG23.15000023.418000JUPITERarchived Oct 20 1999 1:31PM  Nov 26 1999 8:07PM 3WAITE
011000111464HRC-SLETG14.76000014.778000JUPITERarchived Oct 20 1999 1:30PM  Nov 26 1999 2:35PM 3WAITE
011000101463ACIS-SNONE22.60000022.364000JUPITERarchived Oct 20 1999 1:29PM  Nov 26 1999 2:10AM 3WAITE

Canceled DDT Observations
CycleSequence NumberObsIDInstrumentGratingApproved Exposure TimeTargetStatusPI Name
1720108518820ACIS-SHETG30.000000CapellacanceledPetre
1720108518819ACIS-SHETG30.000000CapellacanceledPetre
1540168717560ACIS-SNONE20.000000CXOJ122518.6+144545canceledHeida
1320082914409ACIS-SNONE8.00000055CnccanceledWheatley
1240129613245HRC-INONE1.000000MAXIJ1659-152canceledJonker
0990093912311ACIS-INONE18.700000ChandraDeepField-ScanceledTananbaum
0990093612214ACIS-INONE40.000000ChandraDeepField-ScanceledTananbaum
089007379577ACIS-INONE30.000000ChandraDeepField-ScanceledTananbaum
089007379576ACIS-INONE2.000000ChandraDeepField-ScanceledTananbaum
072004618475ACIS-INONE10.000000L1415EXorcanceledKastner
073001827301ACIS-SHETG15.000000RSOphcanceledStarrfield
073001817300ACIS-SHETG15.000000RSOphcanceledStarrfield
073001807299HRC-SLETG20.000000RSOphcanceledStarrfield
062003656206ACIS-SNONE8.333333V1118OricanceledAudard
062003646205ACIS-SNONE8.333333V1118OricanceledAudard
041000525328HRC-INONE2.500000MooncanceledDrake
041000525313HRC-INONE4.700000MooncanceledDrake
045004144450ACIS-SNONE20.000000SN2002iccanceledHughes
034002693723ACIS-SNONE30.000000MACHO-99-BLG-22canceledReynolds
035002993497ACIS-SNONE25.000000SN2001IGcanceledSchlegel
034002453470ACIS-SNONE10.000000RXJ170930.2-263927canceledJonker
034002443469ACIS-SNONE10.000000RXJ170930.2-263927canceledJonker
034002433468ACIS-SNONE10.000000RXJ170930.2-263927canceledJonker
034002423467ACIS-SNONE5.000000RXJ170930.2-263927canceledJonker
034002413466ACIS-SNONE5.000000RXJ170930.2-263927canceledJonker
034002403465ACIS-SNONE5.000000RXJ170930.2-263927canceledJonker
031000333446ACIS-SNONE8.000000C/2002C1canceledDennerl
035002903440ACIS-SNONE25.000000SN2002APcanceledSchlegel
035002893439ACIS-SNONE25.000000SN2002APcanceledSchlegel
035002883438ACIS-SNONE25.000000SN2002APcanceledSchlegel
033000883435ACIS-SNONE25.000000IMNORMAEcanceledStarrfield
037006143421ACIS-SNONE30.000000MGJ0414+0534canceledChartas
037006133420ACIS-SNONE30.000000MGJ0414+0534canceledChartas
027006113398ACIS-SNONE30.000000MGJ0414+0534canceledChartas
027006103397ACIS-SNONE30.000000MGJ0414+0534canceledChartas
027006093396ACIS-SNONE30.000000MGJ0414+0534canceledChartas
011000273379ACIS-SNONE9.000000COMET19P/BORRELLYcanceledDennerl
011000273378ACIS-SNONE9.000000COMET19P/BORRELLYcanceledDennerl
011000273377ACIS-SNONE9.000000COMET19P/BORRELLYcanceledDennerl
011000272517ACIS-SNONE9.000000COMET19P/BORRELLYcanceledDennerl
023000642511ACIS-SNONE10.000000WZSGEcanceledWheatley
023000632510ACIS-SNONE10.000000WZSGEcanceledWheatley
023000622509ACIS-SNONE10.000000WZSGEcanceledWheatley
023000552466ACIS-SNONE2.000000CIAQLcanceledGreiner
025002022461ACIS-SNONE5.000000SGR1900+14canceledKouveliotou
025002012460ACIS-SNONE5.000000SGR1900+14canceledKouveliotou
025001982457ACIS-SNONE20.000000SGR1900+14canceledKulkarni
014001131847ACIS-SNONE5.000000XTEJ1550-564canceledTomsick


Sequence Number: 502973

Title : X-rays as a probe of the progenitor of the Type Ia SN2017cbv
PI: Drout
Abstract: SN2017cbv is a nearby, bright, and young Type Ia SN that was recently
discovered in NGC 5643 (d~15 Mpc) within hours of explosion. Despite
their importance for Cosmology, questions still remain regarding the
nature and diversity of the progenitors that give rise to Type Ia SN.
Progress can be made by obtaining deep X-ray observations---which
probe the density of the CSM shaped by the progenitor system---for SN
which also have tight constraints on their final progenitor
configuration from early (1-2 day) optical/UV light curves. SN2017cbv
represents a rare opportunity when both sets of constraints are
possible. By timing X-ray observations with optical peak, we can probe
densities as low as a few d-9 Msun/yr, enabling us to distinguish
between many giant, main sequence, and double-degenerate progenitors.
SN2017cbv would represent only the third Type Ia SN for which such
deep limits are possible and this study may lead to the first
detection of X-ray radiation from a Type Ia SN.


Sequence Number: 401892

Title : Puzzling clump with 'whiskers' ejected from a binary
PI: Pavlov
Abstract: Three ACIS-I observations of 2011-2014 allowed us to discover an
extended object moving southwest from the famous high-mass gamma-ray
binary PSR B1259-63/LS 2883 with a surprisingly high velocity, ~0.06c,
perhaps even with acceleration. Such a phenomenon had never been
observed previously. We interpreted it as a clump of stellar matter
ejected from the disk around the massive star near binary periastron
and accelerated and illuminated by the unshocked pulsar wind. The
clump disappeared by 2015 Apr, but a new one was seen emerging from
the binary in 2016 Jan. The latest observation of 2017 Jan 6 showed
the new clump had moved southwest, but its morphology was very
unusual. Most notably, the elongated clump was crossed by narrow
"whiskers" perpendicular to the direction of motion. In addition, a
new extended feature was seen emerging northward from the binary. To
study the evolution of these unexpected features, we request a DDT
observation in April 2017.


Sequence Number: 703466

Title : M87 with Chandra and the Event Horizon Telescope
PI: Neilsen
Abstract: X-ray observations of accreting black holes are ideal for probing the
physical plasma processes close to the event horizon, which can
include both jet formation and magnetic reconnection leading to flares
and variability. Our ability to study these processes is about to take
a major step forward with the Event Horizon Telescope. During the
period April 5-April 14, the EHT will be online with ALMA and 7 other
stations around the world, and its observations of Sgr A* and M87 may
be the first set of observations capable of resolving the shadow of
these important supermassive black holes. But the ability to interpret
EHT data relies on a proper understanding of the plasma processes and
accretion structure around the black hole, as provided by Chandra. We
have arranged coordinated Sgr A* time; here we are requesting Chandra
time on M87 to probe variability and spectra of the accretion flow and
the jet knot HST-1.


Sequence Number: 703466

Title : M87 with Chandra and the Event Horizon Telescope
PI: Neilsen
Abstract: X-ray observations of accreting black holes are ideal for probing the
physical plasma processes close to the event horizon, which can
include both jet formation and magnetic reconnection leading to flares
and variability. Our ability to study these processes is about to take
a major step forward with the Event Horizon Telescope. During the
period April 5-April 14, the EHT will be online with ALMA and 7 other
stations around the world, and its observations of Sgr A* and M87 may
be the first set of observations capable of resolving the shadow of
these important supermassive black holes. But the ability to interpret
EHT data relies on a proper understanding of the plasma processes and
accretion structure around the black hole, as provided by Chandra. We
have arranged coordinated Sgr A* time; here we are requesting Chandra
time on M87 to probe variability and spectra of the accretion flow and
the jet knot HST-1.


Sequence Number: 703465

Title : X-ray flux of the Narrow-Line Seyfert 1 galaxy WPVS 007 during a high
UV flux state
PI: Grupe
Abstract: We request a short, 10ks, observation with Chandra ACIS-S of the
highly X-ray variable Narrow Line Seyfert 1 Galaxy WPVS 007
quasi-simultaneously with HST between March 13 and 26. WPVS 007 is one
of the most unusual AGN showing strong variabilty in broad absorption
lines - a feature that is only seen in high-luminous quasars. We have
monitored WPVS 007 since October 2005 with Swift, but we can typically
not detect it in X-rays. Our last observation of WPVS 007 by Chandra
in March 2015 when it was fount to be in an extremely low UV flux
state (Leighgly et al. 2015) found it at a level of 8e-4 counts/s in
ACIS-s corresponding to a flux in the 0.3-10 keV band of 1e-17 W/m2.
Merging all Swift observaton since then (66ks) results in an 3sigma ul
of 1.4e-17 W/m2. Obtaining a Chandra observation close to the HST
observation will provide us with a crucial flux measurement that will
allow us to determine the intrinsic luminosity of the AGN. Note,
WPVS007 is currently at a bright UV state.


Sequence Number: 401891

Title : A Hig-Resolution Spectrum of the Black Hole GRS 1716-249
PI: Miller
Abstract: This black hole has been in outburst for several weeks, but it has
only recently become visible with the Swift/XRT and Chandra. The
strong outburst (0.2-0.3 Crab) has been visible with the BAT. On
January 27, we requested a Swift DDT of the source, and the resulting
spectrum is strongly encouraging. The source shows a strong, broad
iron line in just a 1 ks exposure, potentially with wind absorption
lines imprinted as well. We are currently attempting to expand the
number of black holes with spin measurements, and to better understand
the duty cycles of outflows. The XRT exposure gives a flux of 6 E-9
erg/cm2/s in the 0.7-10 keV band. Experience suggests that a 30 ks
HETG spectrum of a source at this flux level will yield a sensitive
Chandra spectrum. A spectrum has been sent to the Director.


Sequence Number: 100168

Title : Observing Jupiter's X-ray aurora during Juno apojove
PI: Jackman
Abstract: We don't know what causes Jupiter's auroral X-ray emission. Several
drivers (reconnection, Kelvin Helmholtz) have been suggested but all
require testing of local magnetic field and plasma to uniquely
constrain the source region of particles which cause the emission. The
Juno spacecraft at Jupiter has recently had a trajectory change and
will soon explore a previously unplanned region on the dawn flank near
the statistical position of the magnetopause boundary. We have
agreement to use in situ Juno data to complement X-ray observations.
We propose to observe during 3 apojoves, when Juno is furthest from
Jupiter. Depending on local solar wind conditions Juno will either
sample the solar wind, magnetosheath, or boundary layer inside the
magnetopause. Multiple observations will allow us to test X-ray
generation mechanisms under a range of external conditions. No other
mission of this type is planned in our lifetime and these orbits are
our only chance to sample this magnetospheric region.


Sequence Number: 100167

Title : Observing Jupiter's X-ray aurora during Juno apojove
PI: Jackman
Abstract: We don't know what causes Jupiter's auroral X-ray emission. Several
drivers (reconnection, Kelvin Helmholtz) have been suggested but all
require testing of local magnetic field and plasma to uniquely
constrain the source region of particles which cause the emission. The
Juno spacecraft at Jupiter has recently had a trajectory change and
will soon explore a previously unplanned region on the dawn flank near
the statistical position of the magnetopause boundary. We have
agreement to use in situ Juno data to complement X-ray observations.
We propose to observe during 3 apojoves, when Juno is furthest from
Jupiter. Depending on local solar wind conditions Juno will either
sample the solar wind, magnetosheath, or boundary layer inside the
magnetopause. Multiple observations will allow us to test X-ray
generation mechanisms under a range of external conditions. No other
mission of this type is planned in our lifetime and these orbits are
our only chance to sample this magnetospheric region.


Sequence Number: 100166

Title : Observing Jupiter's X-ray aurora during Juno apojove
PI: Jackman
Abstract: We don't know what causes Jupiter's auroral X-ray emission. Several
drivers (reconnection, Kelvin Helmholtz) have been suggested but all
require testing of local magnetic field and plasma to uniquely
constrain the source region of particles which cause the emission. The
Juno spacecraft at Jupiter has recently had a trajectory change and
will soon explore a previously unplanned region on the dawn flank near
the statistical position of the magnetopause boundary. We have
agreement to use in situ Juno data to complement X-ray observations.
We propose to observe during 3 apojoves, when Juno is furthest from
Jupiter. Depending on local solar wind conditions Juno will either
sample the solar wind, magnetosheath, or boundary layer inside the
magnetopause. Multiple observations will allow us to test X-ray
generation mechanisms under a range of external conditions. No other
mission of this type is planned in our lifetime and these orbits are
our only chance to sample this magnetospheric region.


Sequence Number: 502972

Title : iPTF17cw: A relativistic broad-lined type Ic supernova discovered by
iPTF
PI: Corsi
Abstract: Broad-lined supernovae of type Ic (BL-Ic SNe) are a rare form of
massive star core collapse. The link between BL-Ic SNe and gamma-ray
bursts (GRBs) was first made for GRB980425/SN1998bw, which showed
strong radio emission indicative of relativistic expansion. With SN
2009bb, we have learned that some BL-Ic SNe have relativistic ejecta,
but no associated gamma-rays. These "engine-driven" explosions are
extremely rare (one per 5-10 years), and represent the missing link
between ordinary (non-relativistic) BL-Ic SNe and GRBs. iPTF17cw is a
BL-Ic SN discovered by iPTF on 07 Jan 2017, while following-up LIGO
trigger G268556. Regardless of its association with the LIGO trigger,
our VLA radio observations show that this is a rare relativistic
(v~0.8c) BL-Ic SN. We ask for X-ray observations to constrain: (i)
emission mechanism (IC vs synchrotron) and (ii) synchrotron cooling
freq. (which, combined with radio observations, can constrain magnetic
field and ambient density).


Sequence Number: 703464

Title : Testing a new method for the identification of dual AGN
PI: Secrest
Abstract: Since most galaxies contain massive black holes, and mergers trigger
nuclear accretion, the hierarchical model of galaxy formation predicts
the existence of binary active galactic nuclei (AGN). Confirmed cases
of dual AGN are rare, with efforts for systematic identification
delivering a low yield of confirmed binaries. However, recent
observational and theoretical work has given a new clue in the hunt
for dual AGN: they may preferentially occur in galaxies with very red
mid-IR colors. We have cross-matched the WISE catalog with the 1300
galaxies in the SDSS MaNGA data release. We find a single galaxy with
sufficiently red WISE color (W1-W2=0.84) to classify it as an AGN. Not
only is the host galaxy clearly a spectacular late stage merger, but
the MaNGA IFU data show that the 2 stellar nuclei (separated by ~7
kpc) have optical emission lines consistent with AGN. However, X-ray
observations are required to confirm 2 separate AGN, rather than
extended radiation from a single source.


Sequence Number: 502971

Title : First Deep X-ray Observations of a Rapid, Luminous and Blue Stellar
Explosion
PI: Margutti
Abstract: We propose the first deep X-ray observations of a rapidly-evolving,
luminous, blue stellar explosion. The new class of rapidly-evolving
luminous transients shows luminosities and time scales of evolution
that challenge the traditional Supernovae (SNe) models. Alternative
scenarios include a failed SN of a stripped star, the detonation of a
helium shell on a white dwarf and a SN shock breaking out from a dense
circumstellar medium. To date, due to their large distances (d>500
Mpc), rapidly evolving luminous transients have only been studied in
the optical/UV regime, which is of thermal origin and it is not
sensitive to the nature of the underlying energy source and properties
of the explosion's fastest ejecta. Here we propose to capitalize on
the unique opportunity to study a recently-discovered, nearby (d=150
Mpc), fast-evolving, luminous transient with Chandra to constrain the
environment and explosion properties of this new class of stellar
explosions for the first time.


Sequence Number: 502970

Title : First Deep X-ray Observations of a Rapid, Luminous and Blue Stellar
Explosion
PI: Margutti
Abstract: We propose the first deep X-ray observations of a rapidly-evolving,
luminous, blue stellar explosion. The new class of rapidly-evolving
luminous transients shows luminosities and time scales of evolution
that challenge the traditional Supernovae (SNe) models. Alternative
scenarios include a failed SN of a stripped star, the detonation of a
helium shell on a white dwarf and a SN shock breaking out from a dense
circumstellar medium. To date, due to their large distances (d>500
Mpc), rapidly evolving luminous transients have only been studied in
the optical/UV regime, which is of thermal origin and it is not
sensitive to the nature of the underlying energy source and properties
of the explosion's fastest ejecta. Here we propose to capitalize on
the unique opportunity to study a recently-discovered, nearby (d=150
Mpc), fast-evolving, luminous transient with Chandra to constrain the
environment and explosion properties of this new class of stellar
explosions for the first time.


Sequence Number: 502969

Title : First Deep X-ray Observations of a Rapid, Luminous and Blue Stellar
Explosion
PI: Margutti
Abstract: We propose the first deep X-ray observations of a rapidly-evolving,
luminous, blue stellar explosion. The new class of rapidly-evolving
luminous transients shows luminosities and time scales of evolution
that challenge the traditional Supernovae (SNe) models. Alternative
scenarios include a failed SN of a stripped star, the detonation of a
helium shell on a white dwarf and a SN shock breaking out from a dense
circumstellar medium. To date, due to their large distances (d>500
Mpc), rapidly evolving luminous transients have only been studied in
the optical/UV regime, which is of thermal origin and it is not
sensitive to the nature of the underlying energy source and properties
of the explosion's fastest ejecta. Here we propose to capitalize on
the unique opportunity to study a recently-discovered, nearby (d=150
Mpc), fast-evolving, luminous transient with Chandra to constrain the
environment and explosion properties of this new class of stellar
explosions for the first time.


Sequence Number: 300401

Title : An X-ray spectrum of a transient supersoft source in the Small
Magellanic Cloud
PI: Maccarone
Abstract: This is a transient supersoft source shown in ATel 9866, where we
found an unabsorbed flux of about 2e-11 in the SMC, with a temperature
of about 80 eV. This object was not in ROSAT, and was also observed by
Swift in response to an optical transient from ASSASN (ATel 9859). The
optical light curves clearly show no nova took place, but we now see a
new supersoft source. It is the first strong case for a supersoft
transient which is not a post-nova. How steady burning starts without
a nova is a mystery, but it may also be a key to understanding the
supersoft sources which are one of the proposed Type Ia supernova
channels. Understanding whether the system has emission lines, pure
continuum, or absorption lines, and which lines it has will determine
whether it really is a supersoft source. Exposure is based on trying
to detect the NVII absorption line at 24.78 Ang expected for a hot WD
(Rauch+ 2010). Tommy Nelson simulated and found a clear detection
requires 50 ksec.


Sequence Number: 401890

Title : Probing disk wind and other properties of 4U 1630-47
PI: Bhattacharyya
Abstract: The accreting Galactic black hole transient 4U 1630-47, which is
currently in outburst, is an ideal source to probe two types of
accreted matter ejection: (1) via disk wind and (2) via jet, both
using the observed narrow spectral lines (Diaz Trigo et al., 2013,
Nature, 504, 206; Neilsen et al. 2014; Diaz Trigo et al. 2014).
Chandra gratings are ideal to study such lines. The source also showed
indications of high-frequency (HF) quasi-periodic oscillations (QPOs)
in a rather high (150-450 Hz) frequency range, which can be extremely
useful to probe the strong gravity regime. The AstroSat satellite,
because of its large area and high timing resolution in a broad energy
band, can potentially detect and measure HF QPOs and probe the source
broadband spectrum and state. Hence, our proposed 30 ks Chandra
exposure, nearly contemporaneous with complementary AstroSat
observations, will provide an excellent way to probe the accretion and
ejection mechanism in the strong gravity regime.


Sequence Number: 401889

Title : Constraining the mass of an IMBH candidate in NGC 3310
PI: Earnshaw
Abstract: While much sought-after, intermediate-mass black holes (IMBHs) have so
far remained elusive. Ultraluminous X-ray sources (ULXs) are a good
place to look for IMBHs, and if one appears in the low/hard state we
would expect it to exhibit steady radio jets. A simultaneous
X-ray/radio observation of such an object would allow use of the
fundamental plane (e.g. Merloni et al., 2003) to measure its mass and
confirm its IMBH status. This method has been successfully used before
to identify NGC 2276-3c as a 5e4 solar mass IMBH in Mezcua et al.
(2015). We have found a radio source in NGC 3310 which coincides with
3 ULXs resolved by Chandra, none of which can be identified as the
X-ray counterpart using current radio data. We have been awarded
EVN/e-MERLIN time to attempt to detect and resolve the radio core,
therefore we request quasi-simultaneous observations of this source to
match the radio source with an X-ray source and provide the X-ray
luminosity from which we can calculate the BH mass.


Sequence Number: 201154

Title : Proxima Cen's Stellar Cycle
PI: Wargelin
Abstract: Based on 15 years of optical monitoring, 4 years of Swift X-ray/UV
data, and 2 HRC observations we find evidence for a 7-yr stellar cycle
in Proxima Cen (dMe5.5), a fully convective star. A stellar cycle is
very exciting because most models of stellar magnetic activity predict
such stars cannot support solar-like cycles. Understanding the
structure and evolution of Proxima's magnetic field is also important
because that's what drives X-ray/UV emission and the stellar wind,
which are important factors in modeling the atmosphere (atmospheric
stripping) and habitability of its newly discovered exoplanet. And as
noted by the discovery announcement, "The robust detection of Proxima
b has only been possible after reaching a detailed understanding of
how the star changes on timescales from minutes to a decade." Further
X-ray measurements are required now, while the cycle appears to be at
a maximum, for confirmaton and to better characterize Proxima's
activity over time.


Sequence Number: 201153

Title : Proxima Cen's Stellar Cycle
PI: Wargelin
Abstract: Based on 15 years of optical monitoring, 4 years of Swift X-ray/UV
data, and 2 HRC observations we find evidence for a 7-yr stellar cycle
in Proxima Cen (dMe5.5), a fully convective star. A stellar cycle is
very exciting because most models of stellar magnetic activity predict
such stars cannot support solar-like cycles. Understanding the
structure and evolution of Proxima's magnetic field is also important
because that's what drives X-ray/UV emission and the stellar wind,
which are important factors in modeling the atmosphere (atmospheric
stripping) and habitability of its newly discovered exoplanet. And as
noted by the discovery announcement, "The robust detection of Proxima
b has only been possible after reaching a detailed understanding of
how the star changes on timescales from minutes to a decade." Further
X-ray measurements are required now, while the cycle appears to be at
a maximum, for confirmaton and to better characterize Proxima's
activity over time.


Sequence Number: 201152

Title : Proxima Cen's Stellar Cycle
PI: Wargelin
Abstract: Based on 15 years of optical monitoring, 4 years of Swift X-ray/UV
data, and 2 HRC observations we find evidence for a 7-yr stellar cycle
in Proxima Cen (dMe5.5), a fully convective star. A stellar cycle is
very exciting because most models of stellar magnetic activity predict
such stars cannot support solar-like cycles. Understanding the
structure and evolution of Proxima's magnetic field is also important
because that's what drives X-ray/UV emission and the stellar wind,
which are important factors in modeling the atmosphere (atmospheric
stripping) and habitability of its newly discovered exoplanet. And as
noted by the discovery announcement, "The robust detection of Proxima
b has only been possible after reaching a detailed understanding of
how the star changes on timescales from minutes to a decade." Further
X-ray measurements are required now, while the cycle appears to be at
a maximum, for confirmaton and to better characterize Proxima's
activity over time.


Sequence Number: 201151

Title : Proxima Cen's Stellar Cycle
PI: Wargelin
Abstract: Based on 15 years of optical monitoring, 4 years of Swift X-ray/UV
data, and 2 HRC observations we find evidence for a 7-yr stellar cycle
in Proxima Cen (dMe5.5), a fully convective star. A stellar cycle is
very exciting because most models of stellar magnetic activity predict
such stars cannot support solar-like cycles. Understanding the
structure and evolution of Proxima's magnetic field is also important
because that's what drives X-ray/UV emission and the stellar wind,
which are important factors in modeling the atmosphere (atmospheric
stripping) and habitability of its newly discovered exoplanet. And as
noted by the discovery announcement, "The robust detection of Proxima
b has only been possible after reaching a detailed understanding of
how the star changes on timescales from minutes to a decade." Further
X-ray measurements are required now, while the cycle appears to be at
a maximum, for confirmaton and to better characterize Proxima's
activity over time.


Sequence Number: 401888

Title : Chandra Spectroscopy of SMC X-3 in Outburst
PI: Coe
Abstract: SMC X-3 is an HMXB and pulsar in the SMC. It is currently in the midst
of an apparently super-Eddington outburst (10^39 erg/s, or about 10x
Eddington for a neutron star). This is the brightest outburst from
50-60 sources traced by Coe et al. over a decade, and a special
opportunity. The predicted HETGS count rates will give sensitive
spectra. Lines from the massive companion wind are anticipated; if the
source is truly super-Eddington very strong outflows should also be
detected since radiation and gas will be strongly coupled. Simulated
40 ks spectra based on recent XRT observations, including plasma
components, predict 3-5 sigma line detections in the HETGS band.
Stronger detections are expected if a super-Eddington outflow is
present. Recent work on ULXs shows that at least one such source is a
super-Eddington neutron star. SMC X-3 is much closer and may offer
insights into the accretion flow geometry and physical processes in
this rare accretion phase.


Sequence Number: 401888

Title : Chandra Spectroscopy of SMC X-3 in Outburst
PI: Coe
Abstract: SMC X-3 is an HMXB and pulsar in the SMC. It is currently in the midst
of an apparently super-Eddington outburst (10^39 erg/s, or about 10x
Eddington for a neutron star). This is the brightest outburst from
50-60 sources traced by Coe et al. over a decade, and a special
opportunity. The predicted HETGS count rates will give sensitive
spectra. Lines from the massive companion wind are anticipated; if the
source is truly super-Eddington very strong outflows should also be
detected since radiation and gas will be strongly coupled. Simulated
40 ks spectra based on recent XRT observations, including plasma
components, predict 3-5 sigma line detections in the HETGS band.
Stronger detections are expected if a super-Eddington outflow is
present. Recent work on ULXs shows that at least one such source is a
super-Eddington neutron star. SMC X-3 is much closer and may offer
insights into the accretion flow geometry and physical processes in
this rare accretion phase.


Sequence Number: 401881

Title : Revealing the nature of the mysterious new SMC Transient: Swift
J003233.6-7306
PI: Kennea
Abstract: Starting June 8th, 2016, the Swift SMC Survey, AKA S-CUBED (Kennea et
al., ATEL #9299), began a weekly shallow X-ray survey of the SMC to
search for >1% L_Edd X-ray transients. We have discovered a new
puzzling X-ray transient Swift J003233.6-7306, on the western edge of
the SMC. A NuSTAR DDT observation revealed a hard X-ray spectrum
(Gamma = 1.7), canonical for a BH LMXB in the low/hard state, or
possibly Be/X-ray binary (common in the SMC). The Swift position is
not consistent with any optical counterpart, which is puzzling if a
binary, however given the error in the position from Swift (~4") we
cannot rule out nearby stars as the counterpart. We request a short
(1ks) Chandra in order to localize this transient to the at least ~1"
accuracy needed to definitively identify any counterpart in deep
optical data obtained on the field by OGLE. A firm detection or
non-detection in optical, given the low absorption towards the source,
would place strong constraints on the object type.


Sequence Number: 502963

Title : Prompt Chandra observations of PSR J1119-6127 and its compact nebula
following its magnetar-like burst
PI: Blumer
Abstract: PSR J1119-6127 is a high-magnetic (B) field pulsar with spin
properties (P=408 ms, age=1.7 kyr, B=4.1e13 G) similar to those of
J1846-0258, the first high-B pulsar to show magnetar-like behavior and
one of a handful for which a braking index has been measured
(n=2.91+/-0.05). Chandra studies of J1119-6127 allowed the first
detection of the X-ray counterpart and revealed the evidence for a
compact and faint pulsar wind nebula (PWN; Gonzalez & Safi-Harb 2003
ApJ, 591, 143). A follow up study found evidence for an elongated jet
to the south, and resolved the PSR spectrum from its compact PWN
spectrum for the first time (Safi-Harb & Kumar, 2008, ApJ, 684, 532).
J1119-6127 is considered as a key source in our understanding of the
physical characteristics and processes that differentiate radio
pulsars from magnetars. Just like J1846-0258 , it was predicted that
J1119-6127 will one day reveal itself as a magnetar after an
occasional burst driven by its high B-field.


Sequence Number: 300392

Title : Down with the King: FO Aqr in an Extended Low State
PI: Kennedy
Abstract: FO Aquarii, the so called king of the intermediate polars, is in an
unprecedented and prolonged faint state. Normally brighter than V =
14, FO Aqr is currently at V ~15 and was as faint as V~15.7 at the
start of 2016 May. The faint state began at unknown time between 2015
Dec. 18 (V = 13.71, S. Dvorak, AAVSO) and 2016 May 6 (V ~ 15.6, our
measurement). (For more, including the long term light curve, see
http://www.astronomerstelegram.org/?read=9216) Recent optical
observations have also shown the pulsations to now have a period of
around 11.1 mins (http://www3.nd.edu/~clittlef/FOaqr.png), suggesting
the 2 accretion poles are currently visible. This may be due to a
change in the accretion geometry. We wish to investigate changes to
the x-ray flux and spectrum, and whether the x-ray spin period, which
was seen to be 20.9 mins by Evans et al. (2004, MNRAS, 349, 715) using
XMM-Newton, has also changed to the 10 mins seen in the new optical
data.


Sequence Number: 401819

Title : Measuring the spin period of XMMU J004855.5-734946 during a large
outburst
PI: Vasilopoulos
Abstract: Spin periods of Be/X-ray binary (BeXRB) pulsars are important for
probing their formation channels and the connection between orbital
period and pulsar spin in XRBs (Knigge+ 2011). From the 120 BeXRBs in
the SMC only 50% have known spin periods, with the majority of them
measured during outburst with ToOs. From the remaining systems only 6
have a known orbital period. XMMU J004855.5-734946 is a BeXRB in the
SMC (Haberl & Sturm 2016, XMM Lx ~(0.03-1)x10^35 erg/s) with a 36.43d
orbital period (Atel#9198), but with no X-ray pulsations detected so
far. On 06/24 a 37s Swift/XRT observation detected the system at
Lx~10^37 erg/s (Atel#9197) following a marginal detection on 06/16
(Lx<5x10^36 erg/s) confirming the onset of a large outburst. A
follow-up 1ks Swift ToO on 06/29 measures an Lx = 8.3x10^36 erg/s.
This is a unique opportunity to measure the spin period of one of the
few BeXRBs in the SMC with known orbital period but unknown spin
period.


Sequence Number: 502667

Title : SGR 1935+2154 in a very active state
PI: Kouveliotou
Abstract: The magnetar SGR 1935+2154 has been active since the middle of May
2016 emitting several bursts per day that have triggered the
Fermi/GBM. The burst intensities have been gradually increasing and on
June 26, 2016 the source emitted a very bright burst indicating
potential extreme further source activity. The source persistent
emission properties are strongly influenced by such activity, both in
timing and spectra. We request a Chandra DDT observation to study the
change of the persistent source properties, and potentially study
similar properties for serendipitously recorded bursts. In particular,
we note that the currently reported Nh (GCN 15590) its 3 times higher
than the one measured in the past (Israel etal. 2016) which leads us
to believe that the recent burst is accompanied with metal enhanced
outflow.


Sequence Number: 502666

Title : Chandra Observations of the Brightest and Closest H-poor Superluminous
Supernova Gaia16apd
PI: Yan
Abstract: Gaia16apd was first triggered as a 17.3 mag transient (now 16.5mag) on
2016-05-16 by GAIA. The first optical spectrum on 2016-05-20.92 UT
classified it as a H-poor superluminous supernova (SLSN-I) at z=0.102
and absolute magnitude of -21.0 (Atel #9071). This makes Gaia16apd one
of the brightest and the closest SLSNe-I. SWIFT observations on
2016-05-21 revealed an extremely UV bright source, 15.3mag at 2310A.
Gaia16apd has similar apparent brightness as ASASN-15lh, the most
luminous SLSN-I ever discovered. ASASN-15lh has been observed by
Chandra, and was reported with detections. Magnetar models (Metzger et
al. 2014,Fig.12) predicted that SLSNe-I should have X-ray emission
post optical-peak. With the predicted fluxes well within the Chandra
limit in 10ksec, Gaia16apd offers the unique opportunity to constrain
theoretical models. The proposed observation will shed light on the
long standing mystery of what powers the luminous optical emission
from SLSN-I.


Sequence Number: 502665

Title : Chandra Observations of the Brightest and Closest H-poor Superluminous
Supernova Gaia16apd
PI: Yan
Abstract: Gaia16apd was first triggered as a 17.3 mag transient (now 16.5mag) on
2016-05-16 by GAIA. The first optical spectrum on 2016-05-20.92 UT
classified it as a H-poor superluminous supernova (SLSN-I) at z=0.102
and absolute magnitude of -21.0 (Atel #9071). This makes Gaia16apd one
of the brightest and the closest SLSNe-I. SWIFT observations on
2016-05-21 revealed an extremely UV bright source, 15.3mag at 2310A.
Gaia16apd has similar apparent brightness as ASASN-15lh, the most
luminous SLSN-I ever discovered. ASASN-15lh has been observed by
Chandra, and was reported with detections. Magnetar models (Metzger et
al. 2014,Fig.12) predicted that SLSNe-I should have X-ray emission
post optical-peak. With the predicted fluxes well within the Chandra
limit in 10ksec, Gaia16apd offers the unique opportunity to constrain
theoretical models. The proposed observation will shed light on the
long standing mystery of what powers the luminous optical emission
from SLSN-I.


Sequence Number: 502664

Title : An outburst of the CCO 1E161348-5055: an accreting neutron star or a
peculiar binary magnetar?
PI: Rea
Abstract: The INS 1E161348-5055 is a Central Compact Object (CCOs) in the center
of the 2kr young SNR RCW103. It has been an intriguing source all
along. Several hypothesis about the nature of 1E1613 have been
proposed as a binary neutron star system, a very slow magnetar or even
a CV (see Pizzolato et al. 2008). The bright thermal X-ray emission of
other CCOs, and the low dipolar B field (~10^11 G), have been
interpreted as evidence of "hidden" strong magnetic fields within the
CCO crusts, burried by accretion. 1E1613 was instead considered an
outlier because of the lack of pulsation, but the presence of a
peculiar 6.4hr periodicity. Our undergoing Swift monitoring of 1E16134
show the source at a flux of a factor of 10 higher, and with a harder
spectrum (PL ~1.7) than usual (see figure in the link). Furthermore,
apparently Swift BAT detected a "possible"burst from this direction
(GCN 19547/GRB 160622A), although its association with the CCO is
still unclear (if any).


Sequence Number: 502663

Title : Understanding the Mass-Loss History of the Progenitors of Type IIn
Supernovae: SN 2016bkv
PI: Patnaude
Abstract: The mass-loss history of massive stars is one of the least understood
and yet fundamental aspects of stellar evolution. HOW and WHEN do
massive stars shed their massive envelopes? Is there a relationship
between the expulsion of the stellar envelope and core-collapse? These
central, yet open questions motivate the present investigation. In
regards to these questions, studying the evolution of a supernova
shock as it interacts with the ejected envelope of the progenitor
provides insight into how much mass was lost and perhaps most
importantly, when it was lost relative to core-collapse. X-ray
emission from the shocked gas probes the dynamics of the interaction
and, when combined with other ongoing and planned multi-wavelength
observations, serves to constrain properties of the surrounding
circumstellar gas and the end-stages of the progenitor's evolution. We
propose to study SN2016bkv in order to understand the final mass-loss
phase prior to the core-collapse of its progenitor.


Sequence Number: 401818

Title : An exceptionally cold neutron star in HETE J1900.1-2455
PI: Degenaar
Abstract: The ~1 km thick crust of neutron stars is strongly heated by nuclear
reactions during accretion outbursts, but cools in quiescence. HETE
J1900.1-2455 continously accreted since 2005, but in 2015 late Oct its
intensity dropped below the detection limit of MAXI. Swift
observations (Mar 7) fail to detect the source, implying Lx (0.5-10 keV) and a very cold neutron star crust of kT<65 eV. This is
highly unexpected, as the crust should have been significantly heated
during the ~9 yr outburst: our studies of 5 other sources after >1 yr
outbursts revealed hot neutron star crusts of >100 eV. This remarkable
result suggests that nuclear heating may not always be efficient, a
scenario that has never been considered to explain exceptionally cold
neutron stars such as SAX J1808.4-3658 and 1H1905+000. With a 30 ks
DDT, we can put firm constraints on the crust temperature in HETE
J1900 (kT~33 eV; Lx~2e30 erg/s), with important implications for
neutron star heating/cooling models.


Sequence Number: 703301

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.


Sequence Number: 703300

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.


Sequence Number: 703299

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.


Sequence Number: 703298

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.


Sequence Number: 703297

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.


Sequence Number: 703296

Title : Image D Of Huchra's Lensed Quasar: Waiting For The Other Shoe To Drop
PI: Pooley
Abstract: In mid-2013, image D of Huchra's Lens began fading precipitously in
the optical (as seen by OGLE). One expects corresponding brightness
changes in X-rays, as the X-ray region is thought to be smaller, by a
factor of 4, than the optical continuum region (Mosquera et al), but
with the changes occurring more rapidly. At the start of the 2014 OGLE
season (MJD 56826), image D was 0.7 mag fainter than in mid-2013. Our
analysis of archival Chandra data shows that there was no X-ray drop
on MJD 56815 compared to Chandra data from mid- to late-2013. This is
somewhat surprising, and it would be even more surprising if image D
were still as bright as on MJD 56815, given the continuing decline in
the optical (during 2015, image D had fallen ~2 mag below its mid-2013
level); this would (uncomfortably) imply that the X-rays and optical
come from separate non-concentric regions. We request a 30 ks
observation of 2237+0305 to determine whether image D has also fallen
by a factor of ~6 in X-rays.


Sequence Number: 502662

Title : SN2005ip awakens: an unprecedented glimpse of explosive mass-loss
10,000 years before core-collapse
PI: Mauerhan
Abstract: SNe interacting with circumstellar material (CSM) have raised critical
questions about the latest phases of massive-star evolution. SN 2005ip
is a case where >15 MSun of CSM was ejected by the luminous blue
variable (LBV) progenitor several years before core collapse,
reminiscent of Eta Car's historic eruption. So far we have no
explanation for the cause of pre-SN eruptions; potential factors
include late nuclear burning stages, or violent binary encounters.
After a decade of steadily fading interaction with stellar wind,
SN2005ip began interacting strongly this month with a distant dense
structure of CSM ejected 10,000 yr before the SN, providing an
unprecedentedly distant look-back time on the progenitor's pre-SN
mass-loss history. The CSM could have an origin similar to the ring
around SN1987A, also launched 10,000 yr before SN. We request DDT
ACIS-S observations of 2005ip before it fades, to measure the
interaction energy and mass of the CSM, in order to elucidate its
origin.


Sequence Number: 300391

Title : The accretion disk of a rare jet-driving symbiotic binary during its
brightest outburst in a ~century
PI: Lucy
Abstract: The current optical outburst (ATel#8653) of the symbiotic star
(interacting white dwarf [WD] + red giant) MWC 560, its brightest in
>87 years, provides a rare opportunity to examine the physics of jet
production in the otherwise well-understood context of WD accretion.
This proposal's goal is to use X-ray emission from the accretion-disk
boundary layer to characterize changes in the disk associated with
strong jet production/acceleration. MWC 560 drives a jet, and optical
spectra taken over 2 months during the peak of the last outburst, 26
years ago, showed Balmer absorption velocities increasing from 3000
km/s to their record velocity of 6000 km/s (Tomov et al. 1990).
300-2800 km/s Balmer troughs have just been observed, suggesting the
early phase of jet acceleration. Chandra will reveal whether the
jet-driving disk remains intact and brightens in X-rays (we expect the
boundary layer to remain optically thin) or the degree to which the
inner disk is evacuated (as in X-ray binaries).


Sequence Number: 300391

Title : The accretion disk of a rare jet-driving symbiotic binary during its
brightest outburst in a ~century
PI: Lucy
Abstract: The current optical outburst (ATel#8653) of the symbiotic star
(interacting white dwarf [WD] + red giant) MWC 560, its brightest in
>87 years, provides a rare opportunity to examine the physics of jet
production in the otherwise well-understood context of WD accretion.
This proposal's goal is to use X-ray emission from the accretion-disk
boundary layer to characterize changes in the disk associated with
strong jet production/acceleration. MWC 560 drives a jet, and optical
spectra taken over 2 months during the peak of the last outburst, 26
years ago, showed Balmer absorption velocities increasing from 3000
km/s to their record velocity of 6000 km/s (Tomov et al. 1990).
300-2800 km/s Balmer troughs have just been observed, suggesting the
early phase of jet acceleration. Chandra will reveal whether the
jet-driving disk remains intact and brightens in X-rays (we expect the
boundary layer to remain optically thin) or the degree to which the
inner disk is evacuated (as in X-ray binaries).


Sequence Number: 703295

Title : Catching a Changing Look Quasar as it retreats to the Shadows for the
Second Time
PI: Tremblay
Abstract: We propose an urgent, exciting, and short (30 ksec) Chandra DDT
observation of Mrk 1018, enabling a first-ever observation of a quasar
returning to an obscured Type 2 (narrow-lined) state *for the second
time*. In 1986, the source was identified as one of the first-known
``changing look" quasars, transitioning from a Seyfert 1.9 to a
Seyfert 1 nucleus. This extreme variability was due either to dramatic
intermittency in the accretion rate, or because an eclipsing cloud
vacated our line of sight, revealing the broad line region. Last week,
in examining our new VLT/MUSE IFU data for this source (obtained as
part of the CARS survey, www.cars-survey.org), we were astonished to
discover that the source has just now reverted *back* to a
narrow-lined Seyfert 1.9. Optical photometry shows that the AGN has
dimmed by an entire magnitude over the past year, and shows no signs
of slowing. Chandra is urgently needed to directly test both
hypotheses (i.e., cloud passage vs. accretion rate change).


Sequence Number: 401817

Title : Confirming X-ray brightening of the PSR J2032+4127 binary system
PI: Ho
Abstract: We propose a 5 ks observation of the radio and gamma-ray pulsar PSR
J2032+4127 and its binary (Be-star) companion MT91-213. Even though
there are many known Be-neutron star binaries, this system is unique
in many ways, including its very long and eccentric orbit, proximity
(1.4 kpc), and careful radio monitoring and timing. Neutron stars in
these types of binaries usually undergo luminous X-ray outbursts
during periastron, as they accrete matter from their Be-star
companion. PSR J2032+4127 will reach periastron in early 2018, and the
anticipated X-ray outburst (and radio monitoring) will provide
important insights into the accretion process and physics of neutron
stars and their magnetic fields. Our proposed short observation is
needed in order to produce a baseline for the upcoming outburst,
especially with several other nearby X-ray bright sources.


Sequence Number: 502661

Title : The Young Type IIP Supernova ASASSN-16at
PI: Grupe
Abstract: We propose to observe a young (~5-day old), nearby (16 Mpc) type IIP
supernova ASASSN-16at with Chandra for 5ks. We tentatively detect the
supernova with Swift XRT. Chandra had observed the field in November
2005, but no X-ray source was found, strengthening the possibility
that the Swift detections are associated with the supernova. However,
precise Chandra astrometry is needed to establish the association.
Detections of SNe IIP this early are rare - only 3 have been detected
in X-rays within the first 10 days. Such very early phase X-ray
detection can put important constraint on its immediate circumstellar
exploding environment, which can subsequently probe the mass loss mode
of the RSG progenitor within a decade before the explosion.
Furthermore, the tentative Swift detection places ASASSN-16at among
the most luminous SNe IIP in X-ray, and the Chandra measurement will
test the recently proposed upper limit on the RSG progenitor mass loss
rate for this class of supernovae.


Sequence Number: 201084

Title : X-ray irradiation and evaporation of a likely ocean planet
PI: Wheatley
Abstract: The super-Earth transiting the bright K star HD97658 (V=7.7) has a
density impling a bulk composition dominated by water. X-ray/EUV
irradiation of the planet is expected to photodissociate the water
envelope and drive a hydrogen-rich wind that should be detectable at
Lyman-alpha with HST/STIS. We have HST transit observations scheduled
for Dec and Jan that are designed to detect the escaping hydrogen and
establish the presence of a water reservoir on HD97658b. This would be
the first signature of an evaporating ocean on an exoplanet. Here we
request Chandra observations to measure the mean X-ray flux of the
star in the hours preceding the two HST observations. This will allow
us to determine the energetic efficiency of atmospheric escape in the
case of detected absorption, or to place limits on the abundance of
water in the absence of absorption. Chandra coverage of both transits
will allow us to interpret variability in water loss in the context of
the changing radiation environment.


Sequence Number: 201084

Title : X-ray irradiation and evaporation of a likely ocean planet
PI: Wheatley
Abstract: The super-Earth transiting the bright K star HD97658 (V=7.7) has a
density impling a bulk composition dominated by water. X-ray/EUV
irradiation of the planet is expected to photodissociate the water
envelope and drive a hydrogen-rich wind that should be detectable at
Lyman-alpha with HST/STIS. We have HST transit observations scheduled
for Dec and Jan that are designed to detect the escaping hydrogen and
establish the presence of a water reservoir on HD97658b. This would be
the first signature of an evaporating ocean on an exoplanet. Here we
request Chandra observations to measure the mean X-ray flux of the
star in the hours preceding the two HST observations. This will allow
us to determine the energetic efficiency of atmospheric escape in the
case of detected absorption, or to place limits on the abundance of
water in the absence of absorption. Chandra coverage of both transits
will allow us to interpret variability in water loss in the context of
the changing radiation environment.


Sequence Number: 502660

Title : Search for an X-ray counterpart from a repeating Fast Radio Burst
PI: Scholz
Abstract: Fast radio bursts (FRBs) are a new class of ms bursts discovered using
the Parkes radio telescope (Thornton et al. 2013). FRBs appear to be
one-off events with very large dispersion measures (DM) that suggest
cosmological distances, but unknown origins. Last year, we discovered
the first non-Parkes FRB 121102, DM=557 pc cm^-3, 3x the predicted
Galactic column (Spitler et al. 2014). Remarkably, we detected ~10
more bright radio bursts in Arecibo data from June at the same DM. We
have just detected another burst on Nov 13th using GBT. The June
bursts suggest a period of 8s. This period is typical of magnetars.
This thus could be an extra-Galactic magnetar, and may solve the FRB
mystery. This sky position has yet to be observed by any X-ray
telescope other than ROSAT whose response is too soft to be useful. We
request Chandra DDT time to search for an X-ray counterpart which
would test the magnetar hypothesis and, crucially, localize the
source, thus enabling an ID of a galaxy host.


Sequence Number: 401816

Title : High Spatial/Temporal Resolution Chandra Follow-up of the 2015
outburst of the X-ray pulsar SMC X-2
PI: Li
Abstract: Accretion and propeller are the major processes driving the pulsar
evolution. SMC X-2, a 2.37s X-ray pulsar (Corbet+ 2000), is one of a
few important examples showing strong accretion outbursts and low
accretion propeller quiescences, occasionally. 2 close (2") possible
optical counterparts, a variable brighter Oe and a stable fainter Be,
have been reported (Schmidtke+ 2006). In 2015 Sep, Swift/BAT and
MAXI/GSC independently detected an outburst at 15 mCrab. A rapid XRT
ToO confirms the result with the best ever accurate localization at
<3.6". But still, depending on how the XRT astrometry is done, both
the reported counterparts can be real. While our analysis on the most
recent XRT data (WT) tentatively shows the spin period is by 0.001s
faster than the one detected by RXTE/ASCA in 2000, a more sensitive
data is required to confirm this. We thus request a 2.8ks timing mode
HRC-S observation to 1) determine the optical companion and 2) verify
spin-up history over the last 15 years.


Sequence Number: 703280

Title : Simultaneous Chandra and NuSTAR Observations of the Highly Obscured
AGN Candidate in NGC660.
PI: Annuar
Abstract: We are using NuSTAR to undertake a detailed investigation of the
obscured AGN population at D<15Mpc. Our latest target is NGC660 where
the presence of an AGN has been ambiguous. However, recently it was
observed to undergo a radio outburst which reveals a bright continuum
source (Argo et al. 2015), coincident with Chandra 2-8 keV emission
from one of the three point sources near the nucleus (<5"). This
confirms and pinpoints the X-ray position of the AGN. Comparisons of
the Chandra flux with the radio emission and other multiwavelength
luminosity indicators indicate that the X-ray flux is suppressed,
suggesting that it is absorbed by a high column of gas. A NuSTAR
observation for this object has been scheduled as part of our program.
The requested Chandra observation is essential to unambiguously
constrain the AGN and isolate it from other sources at <8 keV. When
combined with NuSTAR, we will then be able to accurately characterise
the 0.5-30 keV spectrum of the AGN for the first time.


Sequence Number: 100155

Title : Chandra Observations of Pluto's Escaping Atmosphere in Support of the
New Horizons Encounter with Pluto
PI: McNutt
Abstract: Current models of Pluto s extended atmosphere remain uncertain.
Applying knowledge gained from studying cometary X-ray emission,
Chandra ACIS-S photometric imaging of X-rays produced by CXE between
the solar wind and Pluto s atmosphere addresses both the atmospheric
density and the interaction of the solar wind with the extended
Plutonian atmosphere. An exploratory measurement on 24 February 2014
for 35 ksec provided a marginal X-ray emission signal from Pluto given
the low solar wind flux at the time. By increasing the observing time
by a factor of 4 (to 140 ksec), the tentative Cycle 15 detection will
be verified or much tighter upper limits on the neutral gas escape
rate will be determined. The timing of the observation is fixed in
time to coincide with the encounter of the New Horizons (NH)
spacecraft with Pluto, a unique in situ event in solar system
exploration. Chandra provides a unique, global and contemporaneous
X-ray measurement of the system.


Sequence Number: 100155

Title : Chandra Observations of Pluto's Escaping Atmosphere in Support of the
New Horizons Encounter with Pluto
PI: McNutt
Abstract: Current models of Pluto s extended atmosphere remain uncertain.
Applying knowledge gained from studying cometary X-ray emission,
Chandra ACIS-S photometric imaging of X-rays produced by CXE between
the solar wind and Pluto s atmosphere addresses both the atmospheric
density and the interaction of the solar wind with the extended
Plutonian atmosphere. An exploratory measurement on 24 February 2014
for 35 ksec provided a marginal X-ray emission signal from Pluto given
the low solar wind flux at the time. By increasing the observing time
by a factor of 4 (to 140 ksec), the tentative Cycle 15 detection will
be verified or much tighter upper limits on the neutral gas escape
rate will be determined. The timing of the observation is fixed in
time to coincide with the encounter of the New Horizons (NH)
spacecraft with Pluto, a unique in situ event in solar system
exploration. Chandra provides a unique, global and contemporaneous
X-ray measurement of the system.


Sequence Number: 401698

Title : Light Echoes from V404 Cyg
PI: Heinz
Abstract: In June 2013, V404 Cyg went into a bright outburst after 26 years of
quiescence. The source flux is now in decline. Swift observations
reveal the presence of four bright rings, caused by scattering off of
interstellar dust clouds between us and the source. This is only the
third fully resolved echo of a Galactic source. Because the distance
to the source is accurately known, it is possible to perform precision
dust tomography and calibrate the use of dust echoes as distance
measure. To reach the required sensitivity, avoid cross contamination
with dispersed spectra of the dust scattering halo, and be able to
accurately model and remove cosmic and particle backgrounds, gratings
observations cannot be used for this science, and we ask for a 30ksec
full frame imaging observation.


Sequence Number: 100155

Title : Chandra Observations of Pluto's Escaping Atmosphere in Support of the
New Horizons Encounter with Pluto
PI: McNutt
Abstract: Current models of Pluto s extended atmosphere remain uncertain.
Applying knowledge gained from studying cometary X-ray emission,
Chandra ACIS-S photometric imaging of X-rays produced by CXE between
the solar wind and Pluto s atmosphere addresses both the atmospheric
density and the interaction of the solar wind with the extended
Plutonian atmosphere. An exploratory measurement on 24 February 2014
for 35 ksec provided a marginal X-ray emission signal from Pluto given
the low solar wind flux at the time. By increasing the observing time
by a factor of 4 (to 140 ksec), the tentative Cycle 15 detection will
be verified or much tighter upper limits on the neutral gas escape
rate will be determined. The timing of the observation is fixed in
time to coincide with the encounter of the New Horizons (NH)
spacecraft with Pluto, a unique in situ event in solar system
exploration. Chandra provides a unique, global and contemporaneous
X-ray measurement of the system.


Sequence Number: 401697

Title : The Next Step for V404 Cyg
PI: Neilsen
Abstract: In May 1989, the black hole V404 Cyg exhibited some of the brightest,
most dramatic variability ever seen from a Galactic X-ray binary. The
spectacular variability, lasting only 1-2 weeks, was followed by a
slow 6 month decay. Given the extremity of the outburst and the
significant deviations from canonical BH behavior, little is
understood about the physics of this remarkable system. A new outburst
began on June 16, but how closely will V404 Cyg follow the BH track
after its initial fireworks have ended? P Cygni profiles are seen in
the optical (ATel 7669). Will V404 Cyg produce a massive X-ray disk
wind? A strong variable iron line has also been reported (ATel #7694).
We propose two 40 ks observations (~2 orbital periods), in 20-30 and
40-60 days, to study the variable Fe line and search for X-ray
absorption diagnostics of the growing wind during the later portions
of the outburst. Even on our time scale, we expect fluxes near 0.25-1
Crab and a factor of ~5 variability.


Sequence Number: 401696

Title : Detecing Super-Eddington Driven Winds in V404 Cyg
PI: King
Abstract: V404 Cyg has gone into outburst(ATEL 7646..7663). The light curve from
its last (1989) outburst was characterized by a dramatic rise starting
May 23 until May 30, where it then plummeted in X-ray flux (Zycki99),
unusual for X-ray binaries. The outburst was also very close to its
Eddington limit (Tanaka89, Zycki99). Super-Eddington accretion can
explain the bizarre light curve behavior, as ejection of accreting
shells driven by radiation pressure may have disrupted the disk and
caused the dramatic decrease in flux. V404 is now in outburst, and we
will examine its behavior with unprecedented spectral resolution with
the Chandra HETG.Based on our previous work with J17091-3624 (King14),
GRO 1655-40 (Miller08), and GRS 1915+105 (Miller in prep), we find
that 40 ksec is sufficient at detecting lines at >3 sigma. Finding
evidence for winds (or lack there of) will have vital implications for
outflow generation during Eddington accretion phases, feedback, and
growth of black holes.


Sequence Number: 401695

Title : Detecing Super-Eddington Driven Winds in V404 Cyg
PI: King
Abstract: V404 Cyg has gone into outburst(ATEL 7646..7663). The light curve from
its last (1989) outburst was characterized by a dramatic rise starting
May 23 until May 30, where it then plummeted in X-ray flux (Zycki99),
unusual for X-ray binaries. The outburst was also very close to its
Eddington limit (Tanaka89, Zycki99). Super-Eddington accretion can
explain the bizarre light curve behavior, as ejection of accreting
shells driven by radiation pressure may have disrupted the disk and
caused the dramatic decrease in flux. V404 is now in outburst, and we
will examine its behavior with unprecedented spectral resolution with
the Chandra HETG.Based on our previous work with J17091-3624 (King14),
GRO 1655-40 (Miller08), and GRS 1915+105 (Miller in prep), we find
that 40 ksec is sufficient at detecting lines at >3 sigma. Finding
evidence for winds (or lack there of) will have vital implications for
outflow generation during Eddington accretion phases, feedback, and
growth of black holes.


Sequence Number: 401694

Title : The brightening of M82: The intermediate mass black hole or ultra
luminous X-ray pulsar?
PI: Brightman
Abstract: Swift XRT monitoring of M82 has shown that the X-ray emission from the
galaxy has increased by a factor of ~4 from its usual 2-10 keV
luminosity of 1x10^40 ergs/s. Previous flux increases have been
attributed to the intermediate mass black hole candidate, X-1,
entering the thermal disk-dominated state (Feng & Kaaret 2010),
however the neighboring source, X-2, recently identified as an ultra
luminous pulsar (Bachetti et al 2014) has also been known to reach
10^40 ergs/s. At 4 arcsec separation, only Chandra can tell which
source is causing the current brightening. With an off-axis
observation with a sub array of pixels to mitigate pile-up, valuable
spectral constraints will be provided by Chandra. Furthermore, if this
Chandra observation is approved, we will trigger a NuSTAR ToO to
measure the high energy spectrum of the source, whichever it may be.


Sequence Number: 502493

Title : Mapping the evolution of SNhunt275 to shed light onto the last
evolutionary stages of Massive Stars
PI: Margutti
Abstract: The mass-loss history of massive stars is one of the least understood
and yet fundamental aspects of stellar evolution. HOW and WHEN do
massive stars lose their hydrogen envelopes? This central, yet
still-open question motivates our investigation. Here we ask for
Chandra observations to map the evolution of the transient SNhunt275
on its way to become a Supernova. SNhunt275 was identified in 2013 as
a luminous outburst from a stellar object in NGC2770. The same star
gave rise to a luminous display earlier this year and recently
underwent a drastic re-brightening and spectral evolution which likely
prelude to a major explosion, in close similarity to SN2009ip. Our
primary goal is to constrain the density and location of the material
in the immediate environment of SNhunt275, and hence the mass-loss
history of its stellar progenitor over the last ~100 yrs. This is only
possible through deep X-ray observations that sample the emission
arising from the shock interaction with the medium.


Sequence Number: 502492

Title : Mapping the evolution of SNhunt275 to shed light onto the last
evolutionary stages of Massive Stars
PI: Margutti
Abstract: The mass-loss history of massive stars is one of the least understood
and yet fundamental aspects of stellar evolution. HOW and WHEN do
massive stars lose their hydrogen envelopes? This central, yet
still-open question motivates our investigation. Here we ask for
Chandra observations to map the evolution of the transient SNhunt275
on its way to become a Supernova. SNhunt275 was identified in 2013 as
a luminous outburst from a stellar object in NGC2770. The same star
gave rise to a luminous display earlier this year and recently
underwent a drastic re-brightening and spectral evolution which likely
prelude to a major explosion, in close similarity to SN2009ip. Our
primary goal is to constrain the density and location of the material
in the immediate environment of SNhunt275, and hence the mass-loss
history of its stellar progenitor over the last ~100 yrs. This is only
possible through deep X-ray observations that sample the emission
arising from the shock interaction with the medium.


Sequence Number: 401693

Title : Snapshot observations of 2S1553-542: determination of the source
nature
PI: Lutovinov
Abstract: We propose to perform a snapshot observation of the transient source
2S1553-542, which demonstrated an outburst last three months. The
current outburst is a third one only detected from this source since
1975 (the second one was in 2007). Previously the source nature was
tentatively proposed as a X-ray pulsar (pulse period 9.3 sec) in the
Be binary system due to the outbursts activity. But no optical
counterpart was established till the moment. One of main reasons of
this is a lack of knowledge of exact coordinates of the source. The
proposed observations at the outburst decay stage is a unique chance
to determine the source coordinates with a high precision, to perform
follow-up observations in optical and infrared wavebands and establish
its nature. Additionally, based on the results of spectral analysis we
will determine if the source is still accreting at low level or we
observe the heated neutron star.


Sequence Number: 401692

Title : The Structure of the Accretion Flow in SAX J1808.4-3658 at Low
Luminosities.
PI: Patruno
Abstract: The accreting pulsar (AMXP) SAX J1808.4-4658 is now in outburst (ATel
#7346). Seven more have been observed, with pulsations at 401 Hz.
Recently, we made two key discoveries: i. the accretion disk of SAX
J1808 might be truncated close to the co-rotation radius (i.e., where
plasma co-rotates with the neutron star) even at the lowest
luminosities (1e33 erg/s). We suspect that this is due to a new type
of accretion flow: the "trapped dead disk" (see
Patruno+2015,arXiv:1504.05048). ii. we have phase-connected *all*
pulsations observed by RXTE (Patruno+, in prep.), having now a 13 year
baseline. This is unprecedented for any AMXP. If we phase connect *one
more outburst* we can constrain the proper motion and variations of
the semi-major axis for the fisrt time. We'd like to find pulsations
at low luminosities (during reflares) and conclusively determine
whether a disk extends down the co-rotation radius. Then phase connect
these pulsations with our previous 13-yr baseline.


Sequence Number: 502491

Title : Search for a Jet Break in the Short GRB 150423A
PI: Berger
Abstract: Understanding the collimation of short GRB jets is critical for
inferring their true energy release and event rate. This not only
impacts our understanding of these explosive events (e.g. energy
extraction and dissipation), but given their likely association to
neutron star binary mergers also feeds into the expected Advanced LIGO
merger rate, and the expected brightness of Advanced LIGO
electromagnetic counterparts. At the present only 4 short GRB jet
opening angle measurements have been made (by our group using Chandra
and XMM), so every additional measurement will have an impact on the
opening angle distribution. Here we request a single 25 ksec Chandra
observation on a timescale of about 7 days post-burst to measure the
decline rate relative to the XRT early data and hence to determine the
jet opening angle. The detection of a break will indicate a jet of
5-10 deg, while a non-detection will point to a broad outflow with >10
deg.


Sequence Number: 401691

Title : Seizing a rare opportunity to catch a disk wind in a neutron star
X-ray binary
PI: Degenaar
Abstract: In low-mass X-ray binaries (LMXBs) a neutron star or a black hole
accretes matter from a low-mass companion star via an accretion disk.
Outflows in the form of X-ray disk winds and radio jets are
universally linked to the accretion process. During low-luminosity
(<1E37 erg/s) "hard" X-ray states radio jets prevail, whereas disk
winds are only seen during high-luminosity (>1E37 erg/s) "soft"
states. Disk winds are now routinely detected and studied in black
hole LMXBs, but much less is known about such winds in neutron star
LMXBs, which are often fainter. Here we propose to seize the rare
opportunity to study the disk wind in a transient neutron star LMXB,
which is currently exhibiting an outburst and entered an X-ray bright
soft state on April 4th. Swift/XRT observations reveal ionized
absorption features at high (>5 keV) energies that are indicative of a
disk wind in this system. Only with the unprecedented spectral
resolution of Chandra/HETG can these features studied in detail.


Sequence Number: 300338

Title : GK Persei in the current dwarf-nova-like outburst
PI: Orio
Abstract: GK Persei is the "all-in-one" white dwarf interacting binary. It can
be classified as a nova (outburst in 1901), as a symbiotic because of
the red giant companion, as a magnetic system (it is an intermediate
polar or IP), as a dwarf nova (every ~2 years it has repeated
disk-instability-related outbursts) and even as a "mini-supernova
remnant" (it has just "made the news" again, with a Chandra
press-release, because of its luminous at-all-wavelengths, and still
expanding shell ejected in 1901). In March a new dwarf- nova-like
outburst started and we have been monitoring it with Swift. The count
rate in the Swift XRT varies between about 1 and about 2 cts/s (ATels
7246, 7248) and the Swift spectrum indicates a main component of the
X-ray flux, a thermal one, that peaks at energy well above the Swift
range - for this reason we have applied also for NuSTAR time. However,
only grating spectra reveal the full physical picture: we plan to
study how GK Per is evolving.


Sequence Number: 201026

Title : The dim state of RW Aur
PI: Schneider
Abstract: In Oct 2014 the well studied young star RW Aur A was unexpectedly
obscured by the tidally disrupted disk of its close but resolved
binary companion RW Aur B (Petrov et al. 2015,
arxiv.org/abs/1503.04158). Such events are extremely rare and provide
us with a chance to directly measure the gas-to-dust ratio of
protoplanetary disk material. We can measure this ratio by comparing
the differences in X-ray absorption (caused by gas) and optical
absorption (caused by dust) before and during the obscuration event.
So far, estimates are highly model dependent; this observation offers
an actual measurement to tightly constrain planet formation models
that currently suffer from our ignorance of reliable disk gas masses.
Such dimming events are short (the only known other such event lasted
180 days) and unpredictable and thus require quick follow-up
observations when seen in a key system such as RW Aur, where the
bright state is already well characterized at optical and X-ray
wavelengths.


Sequence Number: 502490

Title : Calibration of the ACIS GRADED mode using the Cas A CCO
PI: Posselt
Abstract: The potential temperature (T) decline of the Central Compact Object
(CCO) in the Cas A SNR is important to probe fundamental physics via
the study of neutron star cooling. An exciting T-decline found from
GRADED(G)-mode observations is called into doubt by results from
subarray FAINT (F) observations. Possible reasons are pile-up and
grade migration in the G-mode. Cross-calibration of the different
instrument setups was not possible previously due the poorly known
spatial distribution of the filter contaminant. We propose a
calibration subarray F observation of Cas A with the CCO centered at
exactly the same chip position as in a contemporaneous G-mode
observation. This will allow us to obtain a contaminant-independent
assessment of the G-mode effects on the CCO spectrum. With this, one
can re-calibrate the past 19 G-mode data sets. Such a
cross-calibration will be also useful to the general X-ray community.


Sequence Number: 401690

Title : Chandra Observation of 'GRB 150301C' / [PFH2005] 622
PI: Burrows
Abstract: On March 1, 2015, Swift responded to a strong hard X-ray flare (1000
cps) in the direction of M31, lasting 20 s. It was initially
classified as a possible GRB and given the name GRB 150301C. The lack
of a soft X-ray counterpart was very puzzling. Further analysis showed
a very weak counterpart at about 100 s after the trigger, but this
faded rapidly. The only sources similar in terms of BAT to XRT flux
ratio are short GRBs and SGR flares, both of which are much shorter in
the duration of the hard X-ray burst than this object. XRT found a
single very faint, but fading, object within the BAT error circle,
coincident with a known X-ray source found in an XMM survey of M31:
[PFH2005] 622. Within the XMM source error circle there are 3 optical
sources. We request a 20 ks Chandra observation to localize the
position of the [PFH2005] 622 and to determine whether it is currently
brighter than the XMM flux of 6.9E-15 cgs.


Sequence Number: 703155

Title : X-ray Flux of the Narrow Line Seyfert 1 Galaxy WPVS 007 during an
unprecidented low UV flux state
PI: Grupe
Abstract: We have monitored the Narrow Line Seyfert 1 galaxy WPVS 007 with Swift
since 9.5 years. During this time it has shown a gradual decline in
its UV flux. While this is somewhat expected, because WPVS 007 has
shown an evolution of broad absorption lines seen by HST (Leighly et
al. 2009), in the February 21 Swift observation we noticed a sudden
drop in it's UV M2 magnitude/flux. A new Swift observation on February
28 not only confirmed this low state, it even showed that the UV flux
had dropped even more to an unprecedented low state in the UV since we
have started monitoring WPVS 007 in October 2005! We were just grated
to continue with weekly monitoring with Swift for the next few weeks
to follow the UV flux. However, we need to compare this UV flux with
the current flux in X-rays. While WPVS 007 showed X-ray flaring in
2010 and 2011, stacking Swift data since 2011 suggest that it has
decayed also in X-rays. WPVS 007 is a link between BAL QSOs and NLS1.


Sequence Number: 401689

Title : X-ray follow-up of a fast radio burst
PI: Petroff
Abstract: A new class of bright, isolated, potentially extragalactic pulses
called fast radio bursts (FRBs) is emerging in radio surveys. Only a
handful of sources are known to-date. No host galaxies or progenitors
have been identified, and some of the population s most basic
properties are still being determined. The only FRB ever followed-up
at X-ray wavelengths showed no transient X-ray emission in
observations beginning 8 hours after the event. Rapid response is
needed to determine if an X-ray counterpart exists. This would be the
first multi-wavelength detection of an FRB. Swift is unable to make
these observations as the source may be too faint for Swift and at the
moment the Swift telescope is moon constrained and cannot take
observations on this source.


Sequence Number: 401688

Title : Simultaneous UV and X-ray spectroscopy with HST and Chandra: observing
wind accretion onto a NS
PI: Oskinova
Abstract: We propose a direct experiment to probe the theory of HMXBs. Currently
we conduct the HST survey of HMXBs (PI Oskinova). The HMXB 4U1700-38
will be observed on Feb 22. From the analysis of the STIS spectra we
will determine mass-loss rate, wind velocity and clumping in the donor
star. We need simultaneously HETGS data to test how X-rays respond to
the changes in the wind. Such experiment was never done before. The
HETGS spectra will probe absorption, variability, and emission lines.
Simultaneous X-ray and UV observations will yield an unprecedented
insight on the processes operating in HMXBs. Chandra observed
4U1700-37 in 2003 (id 657) but in different phase. The RGS spectrum is
relatively featureless, while emission lines are prominent in the
HEGTS range. The HEG+MEG count rate varies erratically between 0.2 cps
and 20 cps. We request 15 ks to fully characterize the X-ray behavior.
Zero order will be most likely piled up, the +1 and -1 order will be
fully useful.


Sequence Number: 703154

Title : A second look for variability in the exceptional Swift J123205.1-1056
PI: Levan
Abstract: Swift J123205.1-1056 is a short, soft outburst detected by Swift. In
the error box is an AGN at z=0.134. CXO observations reveal a second
X-ray source on the stellar field of this AGN. If associated (the
probability of chance alignment is low) it has L_X ~ 1e43 ergs/s. This
luminosity suggests either an "afterglow"-like event, or if persistent
a hyperluminous, non-nuclear X-ray source. In the former case it is
possible given the softness of the burst that we may be observing a
tidal flare-like event, in which case a WD-IMBH disruption within a
globular cluster in the galaxy is possible (this is a luminous galaxy
that may contain a high specific frequency of globular clusters, but
has little/no star formation). A repeat of the earlier CXO
observations will allow us to assess variability in the source. Strong
variability would point to a transient event, most likely related to
the gamma-rays. No variability would imply a persistent HLX, but would
still be of considerable interest.


Sequence Number: 502489

Title : Understanding the nature of the peculiar transient Swift
J123205.1-105602
PI: Troja
Abstract: Swift recently triggered on a short duration transient dubbed Swift
J123205.1-105602. Its unusual soft spectrum seems not to be consistent
with a typical short-hard GRB, and its nature is still not well
understood. An optical counterpart was found at the edge of a nearby
galaxy at redshift z=0.093, placing this event within the sensitivity
of advanced LIGO/Virgo. The X-ray emission detected by the Swift/XRT
appears constant, which is also unusual for a typical GRB afterglow.
We request rapid Chandra observations in order to: 1) accurately
localize the X-ray transient, robustly associate it to the optical
counterpart, and eventually detect possible contaminating sources
within the XRT point spread function; 2) constrain the spectral shape
in order to better understand the nature of this object (e.g. neutron
star merger, shock breakout, tidal disruption event).


Sequence Number: 502488

Title : The unprecedented metamorphosis of SN2014C
PI: Margutti
Abstract: The mass-loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. HOW and WHEN do massive
stars lose their hydrogen envelopes? This central, still-open question
motivates our present investigation. Here we ask for a continuation of
our Chandra program to map the unique situation of the interaction of
a hydrogen-stripped supernova 2014C with a thick, hydrogen-rich shell
ejected by the progenitor star, as part of our multi-wavelength (mm to
gamma-rays) follow-up. Our primary goal is to constrain the density
and location of the material in the immediate environment of SN2014C,
and hence the mass-loss history of its stellar progenitor.


Sequence Number: 502487

Title : The unprecedented metamorphosis of SN2014C
PI: Margutti
Abstract: The mass-loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. HOW and WHEN do massive
stars lose their hydrogen envelopes? This central, still-open question
motivates our present investigation. Here we ask for a continuation of
our Chandra program to map the unique situation of the interaction of
a hydrogen-stripped supernova 2014C with a thick, hydrogen-rich shell
ejected by the progenitor star, as part of our multi-wavelength (mm to
gamma-rays) follow-up. Our primary goal is to constrain the density
and location of the material in the immediate environment of SN2014C,
and hence the mass-loss history of its stellar progenitor.


Sequence Number: 502486

Title : The unprecedented metamorphosis of SN2014C
PI: Margutti
Abstract: The mass-loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. HOW and WHEN do massive
stars lose their hydrogen envelopes? This central, still-open question
motivates our present investigation. Here we ask for a continuation of
our Chandra program to map the unique situation of the interaction of
a hydrogen-stripped supernova 2014C with a thick, hydrogen-rich shell
ejected by the progenitor star, as part of our multi-wavelength (mm to
gamma-rays) follow-up. Our primary goal is to constrain the density
and location of the material in the immediate environment of SN2014C,
and hence the mass-loss history of its stellar progenitor.


Sequence Number: 703152

Title : A High-resolution Spectrum of an Unprecedented Tidal Disruption Event
PI: Miller
Abstract: ASASSN-14li is the best possible tidal disruption flare (TDF). Its
host galaxy is at z = 0.02, whereas the prior X-ray bright event
(Swift J16444) was at z = 0.35. The position of this transient is
within 0.04" of the host galaxy. The source was previously quiescent,
and the optical spectrum - both before and after the flare - are
inconsistent with an active Seyfert nucleus. The most recent flux (Dec
2) measured with the Swift XRT is 2 E-11 erg/cm2/s in the 0.2-2.0 keV
band. A moderately deep integration will give a spectrum that should
compare well with Seyfert spectra. There is only weak galactic
absorption along the line of sight to this source (few E+20 cm^-2),
meaning that the low temperature emission (kT = 66 eV) will give an
excellent spectrum at long wavelengths. If the disrupted gas is
illuminated by the central engine, it is reasonable to expect
optically thin line emission on top of a thermal continuum. Please
see: http://www.astronomerstelegram.org/?read=6777


Sequence Number: 703152

Title : A High-resolution Spectrum of an Unprecedented Tidal Disruption Event
PI: Miller
Abstract: ASASSN-14li is the best possible tidal disruption flare (TDF). Its
host galaxy is at z = 0.02, whereas the prior X-ray bright event
(Swift J16444) was at z = 0.35. The position of this transient is
within 0.04" of the host galaxy. The source was previously quiescent,
and the optical spectrum - both before and after the flare - are
inconsistent with an active Seyfert nucleus. The most recent flux (Dec
2) measured with the Swift XRT is 2 E-11 erg/cm2/s in the 0.2-2.0 keV
band. A moderately deep integration will give a spectrum that should
compare well with Seyfert spectra. There is only weak galactic
absorption along the line of sight to this source (few E+20 cm^-2),
meaning that the low temperature emission (kT = 66 eV) will give an
excellent spectrum at long wavelengths. If the disrupted gas is
illuminated by the central engine, it is reasonable to expect
optically thin line emission on top of a thermal continuum. Please
see: http://www.astronomerstelegram.org/?read=6777


Sequence Number: 401686

Title : A second HLX-1-like object in CXO J122518.6+144545
PI: Heida
Abstract: Intermediate mass black holes are crucial as building blocks for
supermassive BHs, but observational evidence for their existence is
still scarce. The brightest ULXs may be good IMBH candidates: the
strongest case is ESO 243-49 HLX-1 (Farrell et al. 2009), an X-ray
source that reaches a luminosity of more than 10E42 erg/s. It is
thought to host a BH of ~20,000 solar masses. Up until now, HLX-1 is
the only known object of its kind. Most candidate ULXs with comparable
luminosities have turned out to be background AGN. Finding more HLX-1
like objects would be an important step forward in the search for
IMBHs. We have investigated the X-ray source CXOJ122518.6+144545
(J1225; Jonker et al. 2010) with Chandra. It was found in an
observation from 2008, at a luminosity of ~2E41 erg/s, making it the
second most luminous ULX after HLX-1. We did not detect the source in
November 2012 and in April and July 2014, but in our last observation
on November 20 it was again visible at ~5E40 erg/s.


Sequence Number: 401685

Title : A second HLX-1-like object in CXO J122518.6+144545
PI: Heida
Abstract: Intermediate mass black holes are crucial as building blocks for
supermassive BHs, but observational evidence for their existence is
still scarce. The brightest ULXs may be good IMBH candidates: the
strongest case is ESO 243-49 HLX-1 (Farrell et al. 2009), an X-ray
source that reaches a luminosity of more than 10E42 erg/s. It is
thought to host a BH of ~20,000 solar masses. Up until now, HLX-1 is
the only known object of its kind. Most candidate ULXs with comparable
luminosities have turned out to be background AGN. Finding more HLX-1
like objects would be an important step forward in the search for
IMBHs. We have investigated the X-ray source CXOJ122518.6+144545
(J1225; Jonker et al. 2010) with Chandra. It was found in an
observation from 2008, at a luminosity of ~2E41 erg/s, making it the
second most luminous ULX after HLX-1. We did not detect the source in
November 2012 and in April and July 2014, but in our last observation
on November 20 it was again visible at ~5E40 erg/s.


Sequence Number: 502485

Title : Deep Chandra observations to put the deepest limits to the density of
the environment around a Type Iax SN
PI: Margutti
Abstract: PSN J12215757+0428185 is a young Type Iax SN. It exploded in M61 and
it is the nearest Type Iax ever found. Here we ask for 20ks of Chandra
observations to constrain the density of the very close environment,
shaped by the mass-loss history of the progenitor system before the
explosion. This observation will allow us constrain the nature of the
progenitor system of this new kind of stellar explosions.


Sequence Number: 703151

Title : An unusual brightening of a non-active galaxy nucleus
PI: Feng
Abstract: NGC 247 is a dwarf or intermediate spiral galaxy at a distance of 3.4
Mpc. Past observations suggest that there was no activity of the
nuclear black hole. We conducted an XMM observation of NGC 247 on 2014
July 1, which serendipitously detected a bright X-ray source
coincident with the nuclear position (within 2 arcsec) with a
luminosity of 2E39 erg/s in 0.3-10 keV. The most recent observation
before that one was made on 2011 Feb 1 with Chandra. There was no
detection in the nuclear region, giving an upper limit of 1E37 erg/s.
If the new X-ray source is indeed due to the nuclear black hole
activity, its sudden brightening suggests that it may have tidally
disrupted a star some time between 2011 and 2014, or start to accrete
a stream of gas at a low rate. Either will be of great interest due to
its rarity and the small distance. A sub-arcsecond position accuracy
is needed to determine if the X-rays arise from the nucleus.


Sequence Number: 703150

Title : A candidate 30,000 solar mass black hole
PI: Gallo
Abstract: The target of this request is a newly discovered 30,000 solar mass
black hole candidate. As part of a follow-up spectroscopic campaign of
SDSS dwarf galaxies with optical signatures of AGN activity (Reines+
2014, ApJ, 775, 24), we recently acquired high resolution
Magellan/MagE spectra of a ~10^9 solar mass galaxy with narrow line
signatures of an AGN. The MagE spectrum clearly reveals the presence
of a broad H_alpha component that was only marginally detected in the
SDSS spectrum. Using standard virial techniques, the measured FWHM and
luminosity correspond a black hole mass of 30,000 solar masses. The
galaxy is a face-on disky dwarf with low Galactic absorption at a
distance of ~100 Mpc. We request 20 ksec with ACIS-S. In conjunction
with the optical diagnostics, the detection of a >10^40 erg/s, point
like X-ray source at a position consistent with the galaxy nucleus
would provide compelling evidence that this dwarf galaxy hosts the
smallest supermassive black hole reported to date.


Sequence Number: 502479

Title : Measuring the period derivative of the newly discovered magnetar SGR
1935+2154
PI: Rea
Abstract: Chandra observed SGR 1935+2154's outburst on the 15th and 28th of July
2014 for 9ks (ACIS-S, TE-mode) and 75ks (ACIS-S CC-mode). We detected
for the first time highly significant, >10sigma, pulsations at a
period of 3.24498(1) s (1 sigma c.l.), confirming it as a magnetar
candidate. Folding directly with this period the first observation we
detect the signal at a lower significance, deriving a period
derivative upper limit of about 2x10^-10 s/s was inferred. Swift
cannot see the signal because the source is too faint. We have
activated our XMM-Newton ToO program to keep monitoring the source,
but the XMM visibility will start on September 27th. We ask here for a
30ks DDT observation with ACIS-S CC-mode around late August to keep
the phase-coherence of our timing solution. This will allow the
determination of the period derivative of this new magnetar, crucial
to define the dipolar surface magnetic field of this object, then
identifying it as a highly-dipolar or low-dipolar magnetar.


Sequence Number: 200968

Title : The new outburst of the EXor V1180 Cas as observed at X and NIR
wavelengths
PI: Nucita
Abstract: EXORs are pre-main sequence stars that show recurrent luminosity
changes of short duration superposed to longer quiescence periods, see
e.g. Audard et al. 2014. Although a general consensus exists about the
nature of such outbursts (i.e. events of enhanced magnetospheric
accretion from the circumstellar disk), the physical mechanisms
regulating the outbursts and how these latter affect the circumstellar
disk structure and its evolution are not clarified yet. We recently
started an observational programme on this class of objects (EXORCISM,
EXOR OptiCal and Infrared Systematic Monitoring, Antoniucci et al.
2013). Optical and near-IR studies of EXORs rapidly increased in the
last decade but little is known about the X-ray properties, in
particular whether X-rays come from the corona of the star (being in
this case unaffected by the outbursts) or, conversely, originate in
accretion events.


Sequence Number: 401615

Title : Chandra/H.E.S.S. follow-up of PSR B1259-63 gamma-ray flare
PI: Bordas
Abstract: PSR B1259-63 is undergoing a flare emission in gamma-rays (ATel
#6204). Such a flare was observed for the first time in 2010,
accounting for almost 100% of the pulsar spin-down power. No flare
counterpart at higher/lower energies was observed at that time,
although the unexpected nature of the event made its MWL coverage
rather poor. We ask for Chandra DDT observations of PSR B1259-63 to
search for the flare X-ray counterpart (2 pointings x 5ksec each
during the next nights) and to monitor itsX-ray/TeV evolution (2
pointings x 5 ksec = 20 ksec from June 16th), in which H.E.S.S. will
observe the source simultaneously. The nature of the GeV flare and its
connection to the X-ray/TeV emission observed during PSR B1259-63
periastron passage makes simultaneous observations crucial. Next
Cherenkov observations will not be possible until 2021. No other X-ray
observatories are available for the requested dates (Swift XRT may not
be available next nights, see GCN 16349).


Sequence Number: 401614

Title : Chandra/H.E.S.S. follow-up of PSR B1259-63 gamma-ray flare
PI: Bordas
Abstract: PSR B1259-63 is undergoing a flare emission in gamma-rays (ATel
#6204). Such a flare was observed for the first time in 2010,
accounting for almost 100% of the pulsar spin-down power. No flare
counterpart at higher/lower energies was observed at that time,
although the unexpected nature of the event made its MWL coverage
rather poor. We ask for Chandra DDT observations of PSR B1259-63 to
search for the flare X-ray counterpart (2 pointings x 5ksec each
during the next nights) and to monitor itsX-ray/TeV evolution (2
pointings x 5 ksec = 20 ksec from June 16th), in which H.E.S.S. will
observe the source simultaneously. The nature of the GeV flare and its
connection to the X-ray/TeV emission observed during PSR B1259-63
periastron passage makes simultaneous observations crucial. Next
Cherenkov observations will not be possible until 2021. No other X-ray
observatories are available for the requested dates (Swift XRT may not
be available next nights, see GCN 16349).


Sequence Number: 502271

Title : Late-time X-rays to constrain the true energy, jet geometry and burst
environment of a GRB from the early Universe (z~6)
PI: Margutti
Abstract: Among the most important parameters to constrain the GRB physics (both
jet launching mechanism and progenitor) are the energy scale, jet
geometry and the burst environment. Those can only be estimated
through broadband modeling of the late afterglow emission (radio to
X-rays). Of particular interest is to constrain the properties of the
z>6 population of GRBs that sample the star formation in the early
Universe (<1Gyr), and understand if they have unique properties when
compared to the overall population. This can only be done if reliable
estimates of the intrinsic properties of high-z GRBs and their
environments are available. Only 3 GRBs have been spectroscopically
confirmed at z>6 (050904, 080913, 090423). GRB140515A at z=6.32 offers
the opportunity to expand the sample. Chandra data acquired at
t+10days (after the flares) are crucial to map the spectrum above the
cooling frequency, thus enabling us to determine the true energy, jet
opening angle and environment of a rare z>6 GRB.


Sequence Number: 401613

Title : A Harder Look at the Bursting Pulsar
PI: Miller
Abstract: Observations of GRO J1744-28 with Chandra and NuSTAR reveal confusing
but potentially very revealing structure within the Fe K region. The
complex is either due to a very odd combination of charge states
within cospatial gas, or it represents double-horned emission line
structure from a truncated accretion disk. This is a significant
challenge to basic ideas of accretion in low-mass X-ray binaries, HETG
resolution can solve it.


Sequence Number: 401613

Title : A Harder Look at the Bursting Pulsar
PI: Miller
Abstract: Observations of GRO J1744-28 with Chandra and NuSTAR reveal confusing
but potentially very revealing structure within the Fe K region. The
complex is either due to a very odd combination of charge states
within cospatial gas, or it represents double-horned emission line
structure from a truncated accretion disk. This is a significant
challenge to basic ideas of accretion in low-mass X-ray binaries, HETG
resolution can solve it.


Sequence Number: 401612

Title : A rare opportunity to resolve the emission line complex in GRO
J1744-28
PI: Kennea
Abstract: Discovered Dec 1995, GRO J1744-28, AKA "The Bursting Pulsar", is one
of only two known objects to exhibit Type-II X-ray bursts. That
outburst lasted ~6 months, and since it has remained in quiescence.
Recently a coordinated effort by Swift, MAXI and Fermi confirmed GRO
J1744-28 to be in its first outburst in ~18 years. With Chandra we
entered the era of high resolution X-ray spectra, however Chandra has
only observed GRO J1744-28 in quiescence, obtaining a very poor
spectrum. ASCA observations (Nishiuchi et al., 1999) detected a 6.7
keV Iron line feature, which is strongly detected in new observations
by Swift. However, the poor spectral resolution of ASCA and XRT do not
allow us to discern the real nature of this feature. With such high
accretion rate, we might expect that the line complex is a blend of
neutral and high ionized lines from disk wind. Only Chandra HETG
observations have the sufficient resolution to pin down the nature of
the X-ray emission lines in GRO J1744-28.


Sequence Number: 401611

Title : The dynamical X-ray nebula powered by the high-mass binary PSR
B1259-63/LS 2883
PI: Pavlov
Abstract: PSR B1259-63/LS 2883 is the famous eccentric gamma-ray binary
(Pbin=3.4 yr, e=0.87) in which a pulsar orbits a massive O-type star.
Using ACIS observations of 2011 December 17 and 2013 May 19, 62 ks
each, we unexpectedly detected an extended (of about 4'' size)
structure, apparently moving away from the binary with v = 0.05c
(arXiv:1312.2654). Such a moving X-ray nebula has never been seen
before. An additional observation before 2014 January 30 is needed to
distinguish between two different interpretations of the extended
emission: (1) a fast-moving cloud of relativistic electrons loaded
with a large amount of baryonic matter; (2) a variable extrabinary
shock in the pulsar wind outflow. If (1) is correct, we will see the
cloud at the same position angle as in May 2013, while the shock would
be seen at a substantially different position angle (corresponding to
the orbital position change since May 2013; see
http://home.gwu.edu/~kargaltsev/B1259.html) if (2) is correct.


Sequence Number: 502269

Title : X-rays to probe the environment and the progenitor of Type Ia SN2014J
PI: Margutti
Abstract: SN2014J has been recently discovered in M82, at a very close distance
of 3.7 Mpc. The spectra indicates a Type Ia supernova explosion. Type
Ia Supernovae have been employed as cosmic ladders to reveal the
accelerating Universe. In spite of their importance for Cosmology, a
key, fundamental question still remain open: Which stars are the
progenitors of these cosmic standards? We ask for deep X-ray
observations, to probe the environment around SN2014J down to
unprecedented limits. By timing the X-ray observations to the time of
the optical peak, and using the formalisms I developed in Margutti
2012 (ApJ 751 134) I will be able to probe densities as low as a few
d-10 Msun/yr (or a few particle/cm3), thus enabling us to distinguish
between symbiotic and double-degenerate progenitors. These limits
would be a factor 10 deeper than the any other limit presented in the
literature so far. It is also possible that this study will lead to
the first detection of X-ray radiation from a Type Ia SN.


Sequence Number: 200967

Title : X-ray driven evaporation of exoplanet atmospheres: discovery of a
uniquely suited test system
PI: Poppenhaeger
Abstract: The evaporation of exoplanetary atmospheres is thought to be driven by
high-energy irradiation. However, the actual mass loss rates are not
well constrained. Co-I Kipping has recently discovered that the star
KOI-314, an M1V dwarf at 65 pc distance, is orbited by two earth-sized
planets, the inner one of them rocky and the outer one gaseous (P_orb
= 14d and 23d). Other recent works have shown an abundance of small
rocky planets in very close orbits around their host stars, suggesting
that the stellar high-energy irradiation evaporates away gaseous
envelopes. KOI-314 is the first nearby system in which earth-sized
planets of both types are detected, allowing us to constrain the
efficiency of planetary evaporation if the stellar X-ray irradiation
is measured. We therefore propose a 10 ks Chandra ACIS-S pointing to
determine the stellar X-ray luminosity and hardness ratio. The
accuracy of the orbital solution decreases quickly due to
Transit-Timing Variations, which is why we ask for DDT.


Sequence Number: 401611

Title : The dynamical X-ray nebula powered by the high-mass binary PSR
B1259-63/LS 2883
PI: Pavlov
Abstract: PSR B1259-63/LS 2883 is the famous eccentric gamma-ray binary
(Pbin=3.4 yr, e=0.87) in which a pulsar orbits a massive O-type star.
Using ACIS observations of 2011 December 17 and 2013 May 19, 62 ks
each, we unexpectedly detected an extended (of about 4'' size)
structure, apparently moving away from the binary with v = 0.05c
(arXiv:1312.2654). Such a moving X-ray nebula has never been seen
before. An additional observation before 2014 January 30 is needed to
distinguish between two different interpretations of the extended
emission: (1) a fast-moving cloud of relativistic electrons loaded
with a large amount of baryonic matter; (2) a variable extrabinary
shock in the pulsar wind outflow. If (1) is correct, we will see the
cloud at the same position angle as in May 2013, while the shock would
be seen at a substantially different position angle (corresponding to
the orbital position change since May 2013; see
http://home.gwu.edu/~kargaltsev/B1259.html) if (2) is correct.


Sequence Number: 401610

Title : Catching the rebirth of a radio millisecond pulsar
PI: Patruno
Abstract: On 2013 Dec 10 we have discovered with a Swift/XRT observation, that
the low mass X-ray binary (LMXB) XSS J12270-4859 has recently changed
state from a quiescent-LMXB into a new anomalous faint state with no
signatures of accretion (ATel #5647). An NTT optical observation
suggests a transition around December 2012 in the opposite direction
to that of the "missing link" PSR J1023+0038 (that switched from a
radio millisecond pulsar (MSP), into an LMXB, Stappers et al.2013,
Patruno et al. 2013). A MSP may therefore be now active in XSS J12270.
We are currently completing the analysis of Parkes data to search for
the putative MSP. The Swift/XRT shows a faint source (1e32-1e33
erg/s). We want now to characterize the spectral behaviour with a 30
ks Chandra pointing. If we do not detect radio pulsations Chandra can
potentially tell us if the pulsar (and pulsar wind) are on even if the
radio pulsar is undetectable (as our preliminary Parkes analysis seems
to suggest).


Sequence Number: 502268

Title : Constraining the progenitor mass-loss and shock parameters around a
very unusual explosion: SN2013ge
PI: Margutti
Abstract: Recent discoveries have shaken our current classification scheme of
supernova explosions. SN2013ge is such a case.The spectra we obtained
within 2 hours since discovery (on Nov 8th) revealed a very unusual
and blue continuum with no sign of H or He. Additionally, the
broadband light-curve of this transient showed an early blue peak
whose origin is unclear. Together, these findings place SN2013ge
outside ANY previously known SN category. We ask for a Chandra
observation to place a solid limit to the environment density (and
hence reveal the mass-loss history of the progenitor) and distinguish
between progenitor types. These observations will also allow us to
constrain the energy density in magnetic fields, a key but poorly
known parameter in SN shock physics. These observations are part of a
multi-wavelength program which includes optical, NIR (both photometry
and spectroscopy), UV and radio observations to obtain the best
constraints to what might represent a new type of SN explosion.


Sequence Number: 502266

Title : A search for absorption features in the afterglow of the unusual GRB
130925A
PI: Bellm
Abstract: GRB 130925A produced several emission episodes triggering Swift-BAT,
Fermi-GBM, and MAXI. The extraordinary length of this emission--over
10^4 seconds--would give GRB 130925A one of the highest total
durations ever observed for a gamma-ray burst. While the initial
bursting phase was similar to that of the the relativistic tidal
disruption event Swift J1644+57, starting at 10^4 seconds after the
trigger this event has entered a steady decay phase without new bursts
(www.swift.ac.uk/xrt_curves/00571830/). Its classification is thus
uncertain, as neither the long GRB class nor Swift J1644 provide
direct parallels. Our NuSTAR spectroscopy during the decay phase has
revealed evidence for a broad absorption feature never previously
observed for either GRB afterglows or for tidal disruption events.
Chandra observations will enable searches for lower-energy lines which
may constrain the ionization state of this unprecedented event.


Sequence Number: 502265

Title : GRB130831A: the birth of a magnetar
PI: De Pasquale
Abstract: Follow-up observations by XRT, UVOT, and ground facilities show Swift
GRB130831A to be an interesting and unusual long GRB at z=0.48, with a
bright optical afterglow. The X-ray light curve of this event
(www.swift.ac.uk/xrt_curves/00568849) displays a rare extremely steep
break from a power-law decay of 1.1 to 5 at ~10^5 s. The standard
forward-shock (FS) fireball model cannot explain the steepness of this
break. Instead it is the signature expected from the spin-down
emission of a newly-born magnetar seen before in short GRBs (Rowlinson
et al. 2013), but only once so far in a long GRB (070110, but 130831A
is a far superior example because the break is much later and we have
better coverage at other wavelengths). With the magnetar emission now
gone, we can measure the FS emission at nu > nu_c (with Chandra; it's
too faint now for Swift) to infer the total energy imparted to the
ejecta and have the first ever measurement of the efficiency of a
magnetar as central engine of a long GRB.


Sequence Number: 502264

Title : GRB130831A: the birth of a magnetar
PI: De Pasquale
Abstract: Follow-up observations by XRT, UVOT, and ground facilities show Swift
GRB130831A to be an interesting and unusual long GRB at z=0.48, with a
bright optical afterglow. The X-ray light curve of this event
(www.swift.ac.uk/xrt_curves/00568849) displays a rare extremely steep
break from a power-law decay of 1.1 to 5 at ~10^5 s. The standard
forward-shock (FS) fireball model cannot explain the steepness of this
break. Instead it is the signature expected from the spin-down
emission of a newly-born magnetar seen before in short GRBs (Rowlinson
et al. 2013), but only once so far in a long GRB (070110, but 130831A
is a far superior example because the break is much later and we have
better coverage at other wavelengths). With the magnetar emission now
gone, we can measure the FS emission at nu > nu_c (with Chandra; it's
too faint now for Swift) to infer the total energy imparted to the
ejecta and have the first ever measurement of the efficiency of a
magnetar as central engine of a long GRB.


Sequence Number: 502037

Title : The Energetics of the High-Redshift GRB 130606A
PI: Berger
Abstract: GRB 130606A at z=5.91 is only the fourth burst at such high redshift
with detected X-ray, optical/near-IR, and radio emission. The data
quality across the spectrum exceeds that of all previous events,
thereby providing a unique opportunity to study the energy scale and
local environment of a massive star explosion in the first Gyr after
the Big Bang. This will allow us to compare the progenitors of the
most distant GRBs to their more typical cousins at redshifts of z~1-3.
The energy scale will shed light the the nature of the explosion,
while the local density will track mass loss from the progenitor prior
to its demise, a direct clue to its nature. Of particular interest is
a measurement of jet collimation that will provide a measure of the
true energy release; strong evidence for such a "jet break" requires
an achromatic break from radio to X-rays. We will combine the
requested Chandra observation with extensive radio and optical/near-IR
data to decipher the GRB properties.


Sequence Number: 601099

Title : A direct constraint on the mass of an IMBH candidate in NGC 2276
PI: Roberts
Abstract: Although long predicted and searched for, a population of
intermediate-mass black holes (IMBHs) has yet to be detected in the
local Universe. We have recently published a small sample of luminous
ULXs that behave like IMBHs in the low/hard state (Sutton et al. 2012
MNRAS 423 1154). If they are in that state, we expect to see steady
radio jets; from these we can directly measure the black hole mass
using quasi-simultaneous X-ray & radio observations to place an object
on the fundamental plane (see e.g. Merloni et al. 2003 MNRAS 345
1057). In VLA follow-up of the sample an IMBH candidate in NGC 2276
was shown to sit at the centre of two extended radio lobes. We have
now been awarded European VLBI network (EVN) observations to attempt
to detect its radio core. Here we ask for quasi-simultaneous Chandra
observations, necessary to resolve the IMBH candidate from two nearby
(within ~5") ULXs and provide the X-ray data point that will allow us
to measure the mass of the black hole.


Sequence Number: 702923

Title : The unusual state of Mrk 590
PI: Mathur
Abstract: Seyfert 1 galaxy Mrk 590 is presently in an unusual state. Its X-ray
soft-excess has disappeared, its optical continuum has practically
vanished, its optical broad emission lines have disappeared, and it
shows the presence of a relativistic outflow. Even the narrow emission
lines have changed. All these observations could be related to each
other, but were taken years apart. We have an approved DDT on HST to
check if the UV continuum and UV broad emission lines have also
vanished and we request contemporaneous Chandra DDT to look for the
presence/ absence of the soft-excess. Together they will help
understand the common underlying cause which could be low accretion
rate relative to Eddington. They will also answer some long-standing
questions in AGN physics such as: What is the origin of the
soft-excess? What is the origin of the broad emission line region? Mrk
590 provides us with an unique opportunity find the underlying physics
related to these apparently disparate phenomena.


Sequence Number: 401541

Title : An intermediate-mass black hole candidate in NGC 404
PI: Kaaret
Abstract: Discovery (Reines et al. 2011, Nature, 470, 66) of a massive black
hole (MBH) in a star-forming dwarf galaxy has shed light on the
relation between MBHs and galaxy formation and evolution. Optical
observations of the star-forming dwarf galaxy NGC 404 suggest it hosts
a 4.5E5 solar mass BH. EVLA observations by Nyland et al. 2012
combined with archival Chandra data show a radio/X-ray source
consistent with a ~1E6 solar mass BH. We have approved European VLBI
Network (EVN) observations to image NGC 404 at 5 mas resolution,
enabling us to eliminate alternative interpretations (SNR, star
forming region). We request contemporaneous Chandra observations to
determine the X-ray state of the source. The source is too dim for
Swift and only Chandra will resolve the BH from surrounding diffuse
emission. In 15 ks, we expect 18 counts in the 2-10 keV band enabling
detection of hard X-ray emission from the BH.


Sequence Number: 401540

Title : Chandra observation of the newly discovered transient IGR J18245-2452
PI: Papitto
Abstract: IGR J18245-2452 is a newly discovered X-ray transient located in the
globular cluster M28 (ATel #4925), which showed a thermonuclear type-I
X-ray burst proving its NS accreting nature (ATel #4959). Optical and
radio counterparts have been proposed (ATel #4981,5003) and a
separate Chandra TOO has been approved to check the source location.
We proposea 60 ks Chandra observation with the HRC to check for any
additional close-by sources in the crowded environment of the
cluster, and to study variability of its emission.


Sequence Number: 100095

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.


Sequence Number: 100094

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.


Sequence Number: 100093

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.


Sequence Number: 702922

Title : Confirm the Nuclear Origin of the Post-flare Hard Spectrum from a
Tidal Disruption Event Candidate
PI: Lin
Abstract: Stars approach a SMBH can be tidally disrupted and subsequently
accreted. Such kind of tidal disrupt events (TDEs) provide a unique
way to find and study inactive SMBHs and may also provide an important
mechanism of growing them. Only about twenty such candidates have been
reported. Following-up of such events is important to constrain their
long-term evolution to help to pin down their nature and strengthen
the TDE theory. TDEs show large dynamic ranges on timescales of years,
allowing to search for possible state transition to test whether
accretion onto SMBHs is similar to that in stellar-mass BH X-ray
binaries. We now need an immediate Chandra observation to confirm the
nuclear origin of a post-flare hard spectrum from our TDE candidate
which has very soft spectra at the flare peak.


Sequence Number: 100097

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.


Sequence Number: 100096

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.


Sequence Number: 100095

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.


Sequence Number: 100094

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.


Sequence Number: 100093

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.


Sequence Number: 901095

Title : Localizing NuSTAR J163433-473838: the First Source Discovered by
NuSTAR
PI: Tomsick
Abstract: A goal of the NuSTAR mission is to study hard X-ray populations in the
Galaxy. While INTEGRAL has carried out a wide survey, uncovering many
new types of interesting and extreme sources (highly energetic PWNe,
new types of HMXBs, etc.), NuSTAR emphasizes going deeper into the
Galactic plane to look for hidden populations. NuSTAR recently found
its first new source, NuSTAR J163433-473838, during an observation of
the Norma spiral arm region. In addition to searching for known
sources in SIMBAD, CSC, etc., we are confident that it is a new source
as Chandra did not detect it during an observation in mid-2011. We are
looking for compact objects in regions with star formation to look for
faint HMXBs that are early in their evolutionary process or perhaps
magnetars or black holes that are expected to be associated with high
mass stars. We are requesting a Chandra observation to localize the
source in order to search for counterparts (e.g., near-IR) to
determine its nature.


Sequence Number: 300318

Title : Understanding the X-ray temperature vs life time dependence of novae
PI: Henze
Abstract: What determines the life time of post-nova outburst supersoft X-ray
sources (SSSs)? A recent fast optical nova in M31 (ATels #4765,4768)
was detected surprisingly early (8 d post-discovery) in a Swift XRT
ToO. An XMM-Newton ToO was granted and unexpectedly revealed a
low-temperature SSS. Later, repeated Swift observations did not detect
the source after only 8 d of activity. This would not only indicate
the fastest SSS evolution of any known nova, it also places the object
well outside recently found correlations between nova parameters, as
only hot novae should evolve fast. However, due to its low-energy
response, Swift could not follow a more gradual decline in X-ray
luminosity and the target is now sun-constrained for XMM-Newton. We
strongly expect to be in agreement with current models and empirical
relations by detecting the nova with Chandra. A non-detection would
severely challenge our understanding of the connections between nova
observables.


Sequence Number: 502032

Title : Investigating the nature of the transient source in M 82
PI: Madej
Abstract: In our Swift X-ray monitoring of M82 we found a new bright transient
which position does not correspond to any of the known sources in this
galaxy. We would like to investigate the nature of this transient
source.


Sequence Number: 200910

Title : Observation of a possible 'orphan' GRB afterglow
PI: Vianello
Abstract: A GRB is highly beamed, while its afterglow is less so. In principle
this should allow to detect orphan afterglows , which has never
happened. The 1.5m MLS telescope of the CRTS discovered a peculiar
transient, which could be such an event. No GRB were detected at or
around that time. An obvious progenitor could be a low-mass star.
However, several co-added MLS images from before does not reveal the
source either, nor do all optical and X-ray surveys. Considering the
prototypical UV Ceti, this flare should have produced a brightening
above 7.5 mags, which would be extremely atypical (Kowalski et al.
2010). Observations with the Palomar 5m telescope (DBSP) and Palomar
1.5m showed no trace of the source (down to ~21st mag) 1 day after,
and 10 days later no photons were detected by Swift/XRT. This is
consistent with a typical afterglow with a power-law decay with
alpha=-1. Confirming the nature of this source would be extremely
valuable for our understanding of GRB afterglows.


Sequence Number: 300317

Title : Nova Mon 2012 as a luminous supersoft X-ray source
PI: Orio
Abstract: Chandra gratings observations of novae in outburst have constrained
the models of accreting and hydrogen burning white dwarfs (novae and
the possible type Ia progenitors) and are allowing unprecedented
discoveries in the nova physics. The supersoft X-ray phase of novae
isthe only way to catch a glimpse of the white dwarf itself, when
hydrogen burning is still ongoing but only a thin atmosphere sits on
top of it. The proposer of this observations has assessed the
theoretical prediction that the white dwarf effective temperature is a
proxy for the white dwarf mass and this has opened many new
possibilities (see Orio 2012, aeXiv 1210.4331). Some novae also show
supersoft emission because of very strong emission lines in the
ejecta, revealing a whole new physics (see also Orio 2012).This nova
is exceptional, it was only one of three detected with the Fermi LAT,
and extremely high energy phenomena seem to happen in the ejecta
(possibly because of large amounts of circumstellar material).


Sequence Number: 702920

Title : Sw1644+57: a relativistic jet that switched on and is now switching
off
PI: Tanvir
Abstract: Sw-J1644+57 was detected as a long-lived gamma-ray outburst in Mar
2011. Its unique H-E properties and location in the nucleus of a small
galaxy at z=0.35, suggested it was due to the tidal disruption of a
star by a 1-10 million Mo black-hole producing a relativistic jet. The
super-Eddington luminosity is understood by the jet pointing towards
us. Subsequent monitoring has shown the emission to decline roughly at
the expected -5/3 power-law for TDE fall-back, till a few weeks ago
when it abruptly "switched off". Our recent XMM data fixes the decline
to be a factor ~100 over only ~60d. Such a rapid shut-down of
accretion (~t^-25) seems implausible, so likely it represents the jet
launching mechanism turning off. We request a CXO observation, several
weeks after the XMM visit, to to establish whether the flux continues
to decline, or stabilises at a low level (eg. due to emission directly
from the accretion disk), thus shedding light on the poorly understood
process of jet production.


Sequence Number: 300316

Title : Grating Spectroscopy of early hard X-ray emission in Nova Mon 2012
PI: Ness
Abstract: The nova Mon 2012 of Aug9 2012 (CBET 3202) has fortuitously been
observed with initial gamma ray emission >100MeV before it was
discovered in optical. Optical observations show similarities with the
ONe nova V382 Vel (1999) (ATel4310). Recent Swift observations yield a
surprisingly bright hard spectrum of a collisional plasma with 3keV
temperature and NH=3E22 (ATel4321), ~10 times the inferred
interstellar value. For these types of spectra we have shown to have
robust model techniques yielding abundances, velocity structure and
ionization state. The only nova grating spectrum of early hard
emission is of RS Oph, but without a giant companion, the origin in
Mon 2012 must be different. Constraining the nova ejecta with a
grating spectrum will illuminate on possible mechanisms for the
production of the initial >100 MeV gamma-rays that may in fact be
general to all high velocity ejection events.


Sequence Number: 502021

Title : The outflow geometry of the short GRB 120804A
PI: Troja
Abstract: The angular size of the GRB outflow is a key ingredient in determining
the total burst energy release and the true events rate. These
parameters are a crucial test for any progenitor and central engine
model. However, despite years of intense follow-up observations, the
degree of collimation of short GRBs still remains a missing piece of
information. Only a few short GRBs display a long-lived, and
relatively bright afterglow, detected in the X-ray, optical, and radio
bands. In these cases meaningful constraints on the jet opening angle
can be placed. We therefore propose to observe the afterglow of
GRB120804A with Chandra a few days after the explosion in order to
search for a jet-break, which is a clean diagnostic tool for
constraining the outflow geometry.


Sequence Number: 502020

Title : 1E 2259+586: Detecting Particle Outflow from an Active Magnetar
PI: Kaspi
Abstract: Magnetars are a class of neutron stars for which the majority of the
radiative output is believed to be powered by the decay of large
(~10E14-10E15 G) magnetic fields. On 2012 April 28, as seen in our
regular Swift monitoring observations, one well-known magnetar, 1E
2259+586, in SNR CTB109, entered a period of enhanced flux (ATel.
4080),and simultaneously suffered a timing anomaly. One proposed
mechanism to explain such outbursts is particle outflow (Thompson et
al. 2000) where large amounts of plasma are advected from the magnetar
at relativistic speeds. This suggests the possibility of a transient
outflow that could result in a jet-like or nebular X-ray structure. A
detection of a transient, small-scale X-ray nebula would be strong
evidence in favor of this model.


Sequence Number: 501800

Title : Disclosing the position of the naked-eye-alike GRB120624B's afterglow
PI: Campana
Abstract: GRB120624B was detected by Swift and Fermi-LAT at very high energies,
but was Moon constrained for Swift follow-up. It is an extremely
bright burst, placing it in the brightest 1% of Swift and Fermi
bursts, only a factor of 2 fainter than the naked-eye GRB080319B. The
lightcurve shows much sub-structure, with hints of periodic behaviour.
A late 10ks Swift XRT observation located an X-ray afterglow candidate
at F_X~8e-14 ergs/s/cm^2. Such a faint X-ray afterglow is very
unusual. Bright bursts such as this one would typically be much
brighter at these times, by factor of ~10 (e.g. Gehrels et al. 2008).
Two deep NIR observations taken with VLT/HAWKI located a candidate,
but it is unusually faint too, and we cannot rule out an unrelated
source. This NIR source is not coincident with the X-ray source. Given
the unique nature of GRB120624B which appears unlike any previously
observed Swift burst, and the significant interest in tracking rare
Fermi-LAT bursts, we request a rapid Chandra ToO.


Sequence Number: 401435

Title : Unveiling an intermediate-mass black hole in the spiral galaxy NGC
4088
PI: Mezcua
Abstract: We have recently detected compact radio emission from the ULX N4088-X1
using the EVN at 1.6 GHz consistent with steady jets from a black
hole. A series of Swift observations obtained around the same time
found the spectrum to be very hard, consistent with the low/hard state
when steady jets are expected. The radio and X-ray luminosities are
consistent with a black hole mass of ~10,000 Msun, however to
accurately measure the mass using the fundamental plane of accreting
black holes we need observations at 5 GHz. To this end we have been
awarded additional 5 GHz EVN observations in early June, and we
request a simultaneous Chandra DDT observation to accurately measure
the mass and confirm the association between the X-ray and radio
emission (for which a sub-arcsecond X-ray position is needed). If
confirmed, this would be the first detection of steady jets from an
intermediate mass black hole (IMBH), and would provide the first
accurate mass measurement of an IMBH.


Sequence Number: 401434

Title : An HETGS Observation of Extreme Activity in 4U 1630-47
PI: Neilsen
Abstract: The black hole candidate 4U 1630-47 recently entered an extremely
bright, active state in its outburst, with X-ray flux varying by a
factor of 4 on timescales of 1 day (mean flux ~0.3 Crab) and strong
hard X-ray emission (as seen by MAXI, Swift/BAT). Our recent
HETG/Suzaku observations of the source in a soft, steady state at 50%
lower flux revealed deep absorption lines from an extremely massive
disk wind. The new active state represents an excellent opportunity to
study how such massive winds respond to strong X-ray variability and
state changes, which have never been probed in 4U 1630-47. Our
proposed 20 ks CC-mode observation will reveal any long- and
short-term modulation in the massive disk wind, while additionally
providing simultaneous probes of any rapid X-ray variability and
changes in the X-ray continuum.


Sequence Number: 401430

Title : Swift J1753.5-0127 in the soft state: signatures of an outflowing
wind
PI: Soleri
Abstract: Miller et al. (2006, Nat., 441, 953) detected absorptions lines in the
Chandra spectra of the black hole GRO J1655-40 in the soft state,
associated with a disc wind. Ponti et al. (2012, MNRAS, 422, L11)
showed that disc winds are common among black holes in the soft state
(but see Neilsen & Homan 2012, ApJ, 750, 27); these winds are more
easily detected in nearly edge-on sources. Swift J1753.5-0127 is a
black hole candidate which has been active since May 2005 and it is
now entering the soft state (Atel #4056). From a fit to a broad Fe
line, Hiemstra et al. (2009, MNRAS, 394, 2080) found that the system's
inclination is high, although no dips or eclipses were observed. We
ask for a 20 ks Chandra observation to detect signatures of a disc
wind, set constraints on the driving mechanisms (which are still
unclear) and estimate the mass loss in the wind. If we also detect the
broad Fe line we can compare its properties to those in the hard
state.


Sequence Number: 300312

Title : Nova LMC 2012 at high spectral resolution
PI: Drake
Abstract: Nova LMC 2012 is the first X-ray bright nova easily accessible to
Chandra gratings to have occurred in Swift Era. Unlike the highly
uncertain distances of novae in the Galaxy, the LMC is at known
distance and nova luminosities can be precisely measured.
Spectroscopic evidence and the fast evolution of the event suggests it
might be a recurrent nova. High resolution X-ray spectra will allow
diagnosis of the radiatively-driven outflow through line profiles, and
will provide a chemical composition snapshot of the supersoft source
envelope. Existing grating observations of novae have shown a diverse
array of spectral features, but recently a pattern has emerged in
which emission lines are stronger for smaller inclination angles. A
Chandra LETG spectrum will provide key insights into the emission
geometry and will help diagnose the processes underlying the
radiatively-driven outflow in what will be a close to Eddington
Luminosity source.


Sequence Number: 401429

Title : An HETGS Observation of the Transient MAXI J1305-704
PI: Miller
Abstract: MAXI J1305-704 is a new X-ray transient, which has come up to a flux
level of 0.07 Crab (see ATEL 4044) and appears to be in a fairly soft
state. Dips have been observed in the X-ray flux, indicating a high
inclination, and possibly also a very short orbital period. This
represents an excellent chance to study the disk atmosphere in this
source, and connections to disk winds. Importantly, the line of sight
column density forthis source is low (1-2 E+21) and will enable
sensitive spectroscopy across the full HETGS band. A 30 ksec
observation of MAXI J1305-704 will yield approximately 1 million
photons in the MEG and HEG, at current flux levels.


Sequence Number: 501797

Title : Supernova PTF 11qcj: first discovery of a radio luminous Ibn
supernova
PI: Corsi
Abstract: PTF 11qcj is a Ibn supernova (SN) discovered by PTF. Its spectra show
He emission lines, related to the interaction with a He-rich dense
shell. Only 4 SNe like this are known, the most famous is SN 2006jc.
11qcj is the only known case of a radio-loud Ibn SN. The Chandra X-ray
light curve of 2006jc supported the He-shell scenario, showing a flux
increase of a factor of 5 in the first 4 months after discovery,
different from the typical power-law decay of X-ray SNe interacting
with a circum-stellar wind. The two Chandra observations of 11qcj
reveal an X-ray luminosity 5x that of 2006jc (at a similar epoch).
Based on the template X-ray behavior of 2006jc, and on the radio
observations we collected so far for 11qcj (the radio emission seems
to track the X-ray behavior), we expect that 11qcj X-ray light curve
is now decreasing. We ask to re-observe 11qcj with Chandra before it
becomes too faint, so as to measure the X-ray light curve FWHM and
constrain the thickness of the dense shell.


Sequence Number: 501796

Title : X-ray followup of type IIP SN 2011ja
PI: Ray
Abstract: We request a Chandra DDT observation of this IIP SN for 60 ks. In our
Chandra observation of 2012Jan10 (39.45 ks exposure, ObsID 13791) we
have detected the SN with 135 counts (0.3-3 keV, background
subtracted) in ACIS-S. A fixed-abs APEC model gives a good fit (kT=
1.6 +- 0.1 KeV and Flux (0.5-2 keV) = 8.8e-15 cgs, with excess
emission at 1.33 keV. The NEI model with free abundance of Mg XI
forbidden line at 1.334 keV can explain the line for a 3.69+/-1.37
fold overabundance of Mg (3 sigma). Both thermal & non thermal Inverse
Compton models can be conclusively ruled out. The line contains 21
counts. As the SN ages the forbidden line should decrease in strength
as gas comes into ionization equilibrium. Chandra observation will
confirm and model the existence of the Mg line and its evolution and
determine the SN ejecta structure. Stacked exposures can detect
further element lines. We have observed it with GMRT (ATel 3899).


Sequence Number: 200830

Title : X-ray irradiation and evaporation of a super-Earth exoplanet
PI: Wheatley
Abstract: The recent discovery that the super-Earth exoplanet 55 Cnc e transits
its 6th mag star provides the exciting opportunity to study the upper
atmosphere of a super-Earth for the first time. Our team has secured
HST DDT with the aim of searching for hydrogen escaping the planet (by
measuring absorption in Ly-alpha through two transits). The planet
density suggests that it may be composed largely of water, in which
case hydrogen evaporation may be expected from a photo-disassociating
super-critical ocean. We propose Chandra observations to measure the
X-ray flux of the host star at the time of both HST observations (on
Mar 7 and Apr 5). Exoplanet evaporation is thought to be driven by
X-ray irradiation, and combined X-ray/UV measurements are required to
measure the mass loss rate and determine the evaporation efficiency.
By measuring X-ray irradiation and the resulting evaporation through
two transits we can begin to study the response of a super-Earth
atmosphere to varying irradiation.


Sequence Number: 200829

Title : X-ray irradiation and evaporation of a super-Earth exoplanet
PI: Wheatley
Abstract: The recent discovery that the super-Earth exoplanet 55 Cnc e transits
its 6th mag star provides the exciting opportunity to study the upper
atmosphere of a super-Earth for the first time. Our team has secured
HST DDT with the aim of searching for hydrogen escaping the planet (by
measuring absorption in Ly-alpha through two transits). The planet
density suggests that it may be composed largely of water, in which
case hydrogen evaporation may be expected from a photo-disassociating
super-critical ocean. We propose Chandra observations to measure the
X-ray flux of the host star at the time of both HST observations (on
Mar 7 and Apr 5). Exoplanet evaporation is thought to be driven by
X-ray irradiation, and combined X-ray/UV measurements are required to
measure the mass loss rate and determine the evaporation efficiency.
By measuring X-ray irradiation and the resulting evaporation through
two transits we can begin to study the response of a super-Earth
atmosphere to varying irradiation.


Sequence Number: 501794

Title : Supernova PTF 11qcj: first discovery of a radio luminous Ibn
supernova
PI: Corsi
Abstract: PTF 11qcj is a Ic supernova (SN) discovered by PTF. Its spectra show
He emission lines, related to the interaction with a He-rich dense
shell. Only 4 SNe like this (called type Ibn SNe), are known. The
prototype is the famous SN 2006jc. The exceptional thing about 11qcj
is that it is radio loud: only this one case of a radio-loud Ibn SN is
know. The Chandra X-ray light curve of 2006jc supported the He-shell
scenario, showing a flux increase of a factor of 5 in the first 4
months after discovery, different from the typical power-law decay of
X-ray SNe interacting with a circum-stellar wind. The Chandra
observation of 11qcj at about 80d since discovery, reveals an X-ray
luminosity 5x that of 2006jc (at a similar epoch). Aim of this
proposal is to track the evolution of 11qcj X-ray light curve, so as
to determine its peak flux and timescale, that are crucial for the
broad-band modeling (currently, we are carrying out an extensive
follow-up campaign in radio, optical, and infrared).


Sequence Number: 501793

Title : Supernova PTF 11qcj: first discovery of a radio luminous Ic SN
interacting with an He shell?
PI: Corsi
Abstract: PTF 11qcj is a Ic supernova (SN) discovered by PTF on 2011 Oct 23. Its
spectrum on day 34 shows He I emission lines which are very rare,
suggesting this a Ibn: a Ic SN interacting with a He-rich cold dense
shell (CDS). Only 4 Ibn SNe are known, the best studied prototype is
the famous SN 2006jc. The Chandra X-ray light curve of 2006jc
supported the CDS scenario, showing a flux increase of a factor of 5
in 4 months, very different from the power-law decay of X-ray SNe
interacting with a circum-stellar wind material (CSM). However, SN
2006jc was undetected in radio. PTF 11qcj may represent the first
discovery of a radio luminous Ibn: our EVLA observations at 40 d
reveal it is 100x more luminous than 2006jc in radio. This suggests
strong CSM interaction which, based on 2006jc, makes a detection with
Chandra likely. We thus request a Chandra observation: measuring the
X-ray luminosity of this event will allow us to constrain the density
of the CDS and confirm the Ibn nature of 11qcj.


Sequence Number: 401427

Title : Chandra Astrometry of a New ULX in NGC 891
PI: Hodges-Kluck
Abstract: A 08/2011 XMM observation of NGC 891 shows a bright (L_X ~ 2E40 erg/s;
F_X ~ 1E-12 erg/s/cm^2) new ULX near the disk. It is absent in
archival X-ray observations. Variability in Swift monitoring and the
absence of bright optical or radio counterparts rule out a SN. As a
bright ULX that recently "turned on" and whose spectrum indicates a
hot (kT ~ 1 keV) disk, the source may be an extreme example of
super-Eddington (5-50 L_Edd) accretion. Deep archival HST images
reveal a potential counterpart--a star cluster--within the 2" X-ray
error circle, but it is only 0.5" across. A better position is a
prerequisite for proposing deep spectroscopic follow-up, and the lack
of radio or optical counterparts in follow-up observations makes CXO
the only option. We expect an ACIS-S count rate of 0.07-0.2 cts/s, and
request 2 ks of DDT time to obtain 150-400 cts, thereby sampling the
PSF extremely well. Although a snapshot is susceptible to flaring, the
ULX is extremely bright.


Sequence Number: 501792

Title : Studying the physics of outbursts in the Westerlund 1 transient
magnetar laboratory
PI: Israel
Abstract: CXOUJ1647 is a transient magnetar which is currently in outburst
(September 2011). The previous one occurred in 2006. Preliminary
analysis of the timing and spectral parameters of the new outburst
suggest a different behaviour with respect to the 2006 event. The main
aims of the DDT request are: the detection of Pdot variations and
therefore of variations of the B-field topology during the 2
outbursts, and monitoring both the spectral and timing evolution in
order to compare them with those of 2006. In particular, the way the
parameters of the two events evolve will allow us to answer to the
following questions: Are all magnetar outbursts originated by large
displacements and/or cracks of the neutron star surface? Are the hot
spots originated by the outburst always occurring on the same places ?
We note that Chandra is currently the only mission able to point to
the source and to achieve a phase accuracy large enough for keeping
the coherency until the next visibility window.


Sequence Number: 501791

Title : Chandra Observations of the Nearest Type Ia SN in 25 Years
PI: Hughes
Abstract: No SN Ia has been detected in the X-ray band during outburst. The most
careful limits have been set using a 20 ks Chandra observation of SN
2002bo in NGC 3190 (22 Mpc), which was observed 9.3 days after
explosion (Hughes et al. 2007), resulting in limits on the
circumstellar medium (CSM) of w = \dot M/ v_w < 1.2E15 g/cm, assuming
a wind density profile \rho_w = \dot M/(4\pi v_w r^2). This limit is
comparable to the limits set by the nondetection of H\alpha flux from
SN 1994D and SN 2001el, although they are less constraining than
limits set in the radio (Panagia et al. 2006). X-ray constraints are
based on direct calculation of the expected emission using
well-understood physics (i.e., bremsstrahlung emission,
Comptonization), while radio limits are subject to large systematic
uncertainties because the efficiency for generating synchrotron
radiation in the shocked wind and ejecta is not known. We will work
with Nikolai Chugai to model and intepret the results.


Sequence Number: 401425

Title : Chandra spectroscopy of the X-ray spectrum of the newly discovered
accreting millisecond pulsar IGR J17498-2921
PI: Di Salvo
Abstract: Papitto et al. (2011, ATel #3556) reported the discovery of a coherent
pulsed signal from the hard X-ray transient IGR J17498-2921 (Gibaud et
al. 2011, ATel #3551) at a frequency of 401 Hz, very similar to the
spin frequency of the first discovered Accreting Millisecond Pulsar
(AMSP) SAX J1808.4-3658. Taking advantage from the reported position
of the source (ATels #3558, #3559) we propose to observe this source
with Chandra/HETG in order to perform X-ray spectroscopy of the X-ray
spectrum of this interesting source and to get invaluable information
on the innermost emitting region. The PCA spectrum shows evidence of a
strong and broad iron emission line at 6.4 keV (sigma = 0.8 keV).
Chandra will be able to confirm that the line is produced at the inner
accretion disc. In this case, fitting with self-consistent reflection
models will give important information on the position of the
magnetospheric radius and on the neutron star magnetic field.


Sequence Number: 401425

Title : Chandra spectroscopy of the X-ray spectrum of the newly discovered
accreting millisecond pulsar IGR J17498-2921
PI: Di Salvo
Abstract: Papitto et al. (2011, ATel #3556) reported the discovery of a coherent
pulsed signal from the hard X-ray transient IGR J17498-2921 (Gibaud et
al. 2011, ATel #3551) at a frequency of 401 Hz, very similar to the
spin frequency of the first discovered Accreting Millisecond Pulsar
(AMSP) SAX J1808.4-3658. Taking advantage from the reported position
of the source (ATels #3558, #3559) we propose to observe this source
with Chandra/HETG in order to perform X-ray spectroscopy of the X-ray
spectrum of this interesting source and to get invaluable information
on the innermost emitting region. The PCA spectrum shows evidence of a
strong and broad iron emission line at 6.4 keV (sigma = 0.8 keV).
Chandra will be able to confirm that the line is produced at the inner
accretion disc. In this case, fitting with self-consistent reflection
models will give important information on the position of the
magnetospheric radius and on the neutron star magnetic field.


Sequence Number: 501789

Title : Is Swift J1834.9-0846 a magnetar related to SNR W41 and HESS
J1834-087?
PI: Kargaltsev
Abstract: J1834.9-0846 triggered the Swift/BAT and the Fermi/GBM on August 7,
2011. Although an SGR-like event was detected in both cases, a spin
period has not yet been found. Our ToO with RXTE will take place on
August 9. We observed the field with Chandra (Misanovic et al. 2010),
searching for a counterpart to an unidentified TeV source HESS
J1834-087 inside SNR W41. We found a point source, CXOU
J183434.9-084443, and offset extended emission. We re-examined these
Chandra (and archival XMM) data and found no point source at the XRT
position of J1834.9-0846, which, however, falls within the extended
structure seen in the Chandra and XMM images. We request 15ks with
ACIS-S to measure the spectrum of the new source, look for possible
compact PWN and pulsations, and perform phase-resolved spectroscopy
and energy-resolved timing. The Chandra data will be jointly analyzed
with the existing HESS and Fermi data. We will use 1/8 subarray to
probe periods as short as 0.4 s.


Sequence Number: 501788

Title : Resolving the mystery of GRB 110709B
PI: Levan
Abstract: We recently observed GRB110709B under our c12 program. This burst was
both very dark (betaOX < -0.4), and unusual in triggering Swift/BAT
twice (separated by ~15 mins). This could indicate a high-z GRB, a
gravitationally lensed burst, or of (another) novel mechanism for GRB
production. Our CXO imaging showed two objects within or close to the
XRT error circle: the 1st (1.2" from XRT centroid) coincides with a
brightening radio source, presumed to be the GRB afterglow; the 2nd
lies at 2.7", and has near identical brightness. The second object may
also be associated with an optical source (which shows weak archival
evidence for variability), but the X/O offset is surprisingly large
(~0.8"). A second CXO visit to search for variability would greatly
clarify this situation. Is the 2nd source simply a chance foreground
object? Does the 1st source behave like a conventional X-ray
afterglow? The major followup devoted to this most unusual GRB makes a
strong case for another visit.


Sequence Number: 501567

Title : Determination of the true nature of Swift J1822.3-1606
PI: Kouveliotou
Abstract: Swift J1822.3-1606 was detected with the BAT during a ground search of
the data; it also triggered the Fermi/GBM when it emitted a series of
~5 Soft Gamma Repeater like X-ray bursts, each one lasting ~ 5 ms. We
observed the persistent emission of the source with the RXTE/PCA and
confirmed the pulse period of 8.4377585 s. Moreover, we determined a
very high pulsed fraction of the signal of at least 41%. This pulsed
fraction is highly unlikely for an SGR. The source could well be
another Swift J1626.6-5156 (most likely a Be-X-ray binary) or
alternatively, another rotation powered pulsar like PSR
J1846−0258, which was detected to emit SGR-like bursts. The
latter option was the first of its kind linking high B-field pulsars
to SGRs. We are seeking CXO/HRC observations of Swift J1822.3-1606 to
determine the most accurate source location, which will enable us to
identify the source counterpart in this congested region. The current
positional accuracy with Swift XRT is 3.5".


Sequence Number: 702582

Title : Swift J2058+0516: A Second Prompt Relativistic Outflow from a Massive
Black Hole?
PI: Cenko
Abstract: The recent discovery of the transient source Swift J1644 has revealed
a potential new class of high-energy outbursts. Like long-duration
gamma-ray bursts, these sources exhibit a prompt, dramatic energy
release which drives a relativistic outflow. However, the central
engine powering these events is the massive black hole at the center
of a normal galaxy. More recently, Swift has discovered another
high-energy transient, Swift J2058, with broadly similar high-energy
properties. Within the XRT localization (1.7" radius), we have
identified the likely optical counterpart as an absorption line galaxy
at z=1.185. At this redshift, the X-ray luminosity (4e47 erg/s) and
X-ray-to-optical flux ratio (12,000:1) are essentially identical to
that observed from Swift J1644. Here we request HRC-I observations of
Swift J2058 to a) provide precise astrometry (to establish or refute a
nuclear origin), and b) measure the variability time scale (to
constrain the mass of the accreting source).


Sequence Number: 401300

Title : Which M15 Source Is Now in Outburst?
PI: Sivakoff
Abstract: On May 16, MAXI detected an X-ray burst from the globular cluster M15.
Today (5/18) Swift confirmed that either the edge-on ADC source AC 211
or the ultracompact (22-min period) M15 X-2 is flaring (L~1.3E37). It
is unlikely that AC 211 is responsible as one does not expect to see
bursts from ADC sources. The standard paradigm for ultracompact XRBs
like M15 X-2 is that they "should" show stable mass transfer. The few
Chandra observations of M15 X-2 have not showed significant
variations, but today's measured luminosity was 10 times that
typically measured. The 17-minute ultracompact XRB in NGC 1851 has
shown variability by factors of >10 (Maccarone et al. 2010, MNRAS,
406, 2087), a behavior that remains unexplained. Determining that a
second ultracompact exhibits large variations would significantly
challenge the standard paradigm for accretion in ultracompact XRBs.


Sequence Number: 501563

Title : Confirmation of a New Pulsar Wind Nebula
PI: Miller
Abstract: We have recently discovered an extended source with dual ring-like
structure in a shallow Swift image in the Galactic Plane. The
structure is strongly suggestive of a pulsar wind nebula. A known B
star is plausibly associated with the extended source, which means
that the neutron star could be in a binary, and that we could capture
an image of a very young X-ray binary that will eventually become a
double neutron-star system. A short Chandra exposure of just 5 ksec
will be sufficient to confirm the structures suggested by the Swift
image, to obtain a spectrum with approximately 4000 photons, and to
enable multi-wavelength follow-up observations in the near future.


Sequence Number: 702581

Title : Chandra Follow-up of an Exceptional GALEX+PS1 Tidal Disruption Event
Candidate
PI: Gezari
Abstract: We propose for a DDT observation of a candidate tidal disruption event
(TDE) discovered in coordinated UV GALEX and optical Pan-STARRS1 (PS1)
observations. The long-lasting blue color (NUV-r < -1.2) during the
slow decay of the flare over 10 months of GALEX+PS1 monitoring is
unlike any known supernova behavior, and is consistent with the hot
blackbody emission and t^(-5/3) luminosity decay of a TDE. X-ray
observations are critical for determining the broadband SED of the
flare, which is theoretically expected to peak in the soft X-rays.
This flare would have satisfied our Chandra Cycle 11 TOO criteria when
it was discovered in 2010 June, however the first optical spectrum
taken on 2010 June 16 detected an isolated broad emission line that
was misidentified as Mg II at z=0.96. A later spectrum taken on 2011
April 7 revealed absorption features from the host galaxy at z=0.170,
indicating that the broad feature was in fact He II, a high ionization
line associated with TDEs!


Sequence Number: 401297

Title : Probing the neutron star crust of the new transiently accreting 11 Hz
X-ray pulsar in the globular cluster Terzan 5
PI: Degenaar
Abstract: A new bright transiently accreting neutron star was discovered in
Terzan 5 in 2010 October. We obtained a Chandra DDT observation in
February, ~2 months after the end of the outburst, and found the
neutron star a factor ~4 hotter than measured in archival Chandra data
(Degenaar & Wijnands 2011a,b). This indicates that the crust was
severely heated during outburst and that it is possible to observe the
crust cooling curve of this source. However, our target likely cools
considerably faster than previous studied sources, because the short
(~2 months) outburst duration only heated the outer layers of the
neutron star crust (see webpage specified below), which loose the
deposited heat already within months. We request a Chandra DDT
observation to further monitor the cooling curve and put important new
constraints on the neutron star crust: the slope of the cooling curve
directly measures the heat flux in the outer crust, hence the amount
and distribution of heat sources.


Sequence Number: 200735

Title : Hot wind and accretion in TW Hya
PI: Guenther
Abstract: We have recently discovered variability in X-ray indicators of
accretion in the CTTS TW Hya. We seek to use this to understand the
physics of accretion in our upcoming HST observations. We have been
granted 10 HST orbits and 15 CRIRES pointings to monitor the C IV 155
nm doublet and the He I 1083 nm line in TW Hya, the closest CTTS, to
correlate i) the hot wind ii) the cool wind iii) the photometric
period iv) the accretion. In existing HETGS data of TW Hya we see
variability in emission lines from the accretion shock on the star.
However, the densities in Ne IX and O VII indicate that today's shock
models are incomplete. A hot wind is the most promising candidate for
this missing component. Our HST observations will characterize the
wind and we ask for 20 ks Chandra time with LETGS/ACIS simultaneous to
HST to determine the state of accretion. The high effective area of
LETGS/ACIS gives > 100 counts in the O VII and Ne IX triplets, so we
can measure the density and temperature.


Sequence Number: 401295

Title : Searching for the pulsar powering the new TeV binary HESS J0632+057
PI: Torres
Abstract: We request 50 ks Chandra time to check for the existence of X-ray
pulsations from HESS J0632+057. The latter is associated with XMMU
J063259.3+054801 / Be star MWC 148 and has shown a recent increase in
X-ray activity, based on Swift-XRT monitoring (ATEL #3152). We have
used this and previous Swift observations (Falcone et al. 2010, ApJ
708, L52) to positively evaluate the Chandra visibility. HESS
J0632+057 was recently discovered (Aharonian et al. 2007, A&A, 469,
L1), and proposed to be a member of just a handle of such binaries
that emit in gamma-rays. Knowing about its composition is essential
for modeling (e.g., Mirabel 2006, Science 1759). Search for pulsations
from gamma-ray binaries with Chandra have provided the most stringent
upper limits yet (Rea et al. 2010, MNRAS 405, 2206), and its detection
would be a breakthrough for the understanding of these systems.


Sequence Number: 401293

Title : Observing the crust cooling in the 11 Hz accreting pulsar in the
globular cluster Terzan 5
PI: Wijnands
Abstract: We have intensively studied the crust cooling of accreting neutron
stars. We have focused on systems with outbursts lasting years to
decades for which observing the crust cooling is most feasible.
However, as already suggested in Brown et al. 1998 (see the link given
in the TOO Trigger criteria section) crust cooling might also be
observable for systems which have a low quiescent temperature and very
bright but short (weeks/months) outbursts. A recent new transient in
Terzan 5 reached ~1E38 erg/s and its outburst lasted at most a few
months. Combined with its very low quiescent temperature (Degenaar &
Wijnands 2011) this source is an ideal target to test this and to
provide valuable input to any crust-cooling model. Adding this source
to our sample will also be very important to understand the observed
differences between sources and whether this is related to their
different outburst properties and further put constraints on the
properties (ie the crust) of accreting neutron stars.


Sequence Number: 401292

Title : Measuring the Spin of the Black Hole Cgynus X-1, Phase 2
PI: McClintock
Abstract: We are about to submit a paper to Science on the near-maximal spin
(a/M>0.97) of Cyg X-1 [1]. This premier result is largely based on two
DDT Chandra (plus RXTE) spectra obtained last July, two weeks after
Cyg X-1 entered its soft state on 7 July. For these observations, the
Compton component was relatively strong ("scattered fraction" f=34%),
well above the established limit of reliability for our spin method,
which is f=25% [1]. In mid-October, Cyg X-1 entered a "supersoft"
state [1], and we now propose to obtain one additional Chandra
observation (HETG; TE mode; 12 ks) in order to secure our result. We
expect to obtain a Compton-weak spectrum with f<25% (like our 1996
ASCA/RXTE spectrum with f=24%) [1]. To date, our group has measured
the spins of 9 black holes, and this result for Cyg X-1 is distinctly
our most important and exciting [2]. REFERENCES: [1]
https://www.cfa.harvard.edu/~lgou/cygx1/cygx1.html [2]
http://arxiv.org/abs/0909.0169 AND http://arxiv.org/abs/1004.3558


Sequence Number: 501549

Title : Unveiling the nature of cyclic behavior in the period evolution of the
Anomalous X ray Pulsar XTE j1810-197
PI: Perna
Abstract: The goal of our analysis is to probe a possible long term (5 yr)
free-body precession of this neutron star for which we found several
indications based on a non-phase-connected timing analysis. Although
only 3 NS up to now have shown indication of precession, such evidence
strongly challenges our current understanding of the NS interior. The
standard picture of the outer core, in which superfluid neutrons
coexist with type II superconducting protons, requires revision. One
possibility is that protons are type I which would imply a significant
revision of our picture of the physical conditions in the NS core.
Another possibility is that the neutrons are normal in the outer core
which again affects our understanding of the physical state of NSs
core. The presence of long period modulation can shed light on the
physical properties of NS and thus help constraining its equation of
state


Sequence Number: 600982

Title : An Unusual Outburst from the Nucleus of the Quiescent Galaxy NGC 1589
PI: Filippenko
Abstract: As part of the Lick Observatory Supernova Search (LOSS), we have
recently identified an unusual optical outburst from the nucleus
(within 0.05";, or 10 pc in projection) of the nearby (d ~ 50 Mpc)
spiral (S0/a) galaxy NGC 1589. Over a decade of photometric monitoring
with LOSS, together with archival spectroscopy from the CfA Redshift
Survey, suggest the galaxy does not harbor an active galactic nucleus.
Likewise, the bright observed X-ray emission and complex H-alpha
emission profile do not appear to resemble any known Type II
supernova. We therefore believe this transient source (dubbed
NGC1589-OT) represents the most viable candidate for a tidal
disruption flare (TDF) ever discovered in real time. Here we request a
10 ks Chandra/ACIS DD observation to accurately constrain the X-ray
spectral properties (power-law vs. thermal) and environment (n_H) of
this unique, fascinating source. In a separate proposal, we are also
requesting HST time to get a UV spectrum of it.


Sequence Number: 501548

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.


Sequence Number: 501547

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.


Sequence Number: 501546

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.


Sequence Number: 501545

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.


Sequence Number: 501544

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.


Sequence Number: 501543

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.


Sequence Number: 501542

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.


Sequence Number: 702511

Title : The bolometric luminosity of the z=7.08 QSO ULAS J1120+0641
PI: Simpson
Abstract: We have recently discovered the most distant QSO, ULAS J1120+0641, at
z=7.08, smashing the previous record of z=6.44. This object was
discovered by surveying 2250deg^2 of UKIDSS and SDSS, extending the
technique used by high-z QSO surveys into the near-IR. Based on its
rest-frame UV luminosity, the QSO is powered by a black hole of mass
~1e9Msun just 760Myr after the Big Bang. The presence of such a
massive collapsed object when the Universe was so young is a serious
challenge to models of structure formation and places strong
constraints on the growth of supermassive black holes in the early
Universe. We propose a CXO observation of ULAS J1120+0641 to measure
its X-ray flux. This will immediately provide a more reliable estimate
of its bolometric luminosity and black hole mass, and is also
necessary for us to determine the feasibility of a deep XMM spectral
observation to measure the X-ray photon index and Eddington ratio, and
compare its X-ray properties with those of other QSOs.


Sequence Number: 401291

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401290

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401289

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401288

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401287

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401286

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401285

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401284

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401283

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.


Sequence Number: 401282

Title : High resolution spectroscopy of the 11 Hz eclipsing pulsar in Terzan
5
PI: Bhattacharyya
Abstract: The observation of the unique neutron star low-mass X-ray binary
(LMXB) EXO 1745-248 during its current outburst holds the promise to
address several important scientific problems. These are (1) use of
narrow absorption and emission features to probe the ionized and
neutral components above the accretion disk of LMXBs (Jimenez-Garate
et al. 2003); (2) measurement of the disk inner edge radius from the
broad relativistic iron line, and hence to probe the strong gravity
regime and the neutron star parameters (Bhattacharyya and Strohmayer
2007; Cackett et al. 2008); and (3) measurement of the neutron star
radius-to-mass ratio from narrow surface atomic spectral lines during
thermonuclear X-ray bursts. An observation with Chandra is required
because (1) it has unique high-resolution spectral capability, and (2)
this satellite will be able to observe the source throughout the
outburst (which XMM-Newton and Suzaku cannot do because of Sun angle
constraints).


Sequence Number: 501540

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.


Sequence Number: 501539

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.


Sequence Number: 501538

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.


Sequence Number: 501537

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.


Sequence Number: 501536

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.


Sequence Number: 501535

Title : Unveiling the nature of cyclic behavior in the period evolution of the
Anomalous X ray Pulsar XTE j1810-197
PI: Bernardini
Abstract: The goal of our analysis is to probe a possible long term (5 yr)
free-body precession of this neutron star for which we found several
indications based on a non-phase-connected timing analysis. Although
only 3 NS up to now have shown indication of precession, such evidence
strongly challenges our current understanding of the NS interior. The
standard picture of the outer core, in which superfluid neutrons
coexist with type II superconducting protons, requires revision. One
possibility is that protons are type I which would imply a significant
revision of our picture of the physical conditions in the NS core.
Another possibility is that the neutrons are normal in the outer core
which again affects our understanding of the physical state of NSs
core. The presence of long period modulation can shed light on the
physical properties of NS and thus help constraining its equation of
state


Sequence Number: 501534

Title : The first low-B soft gamma repeater: testing the magnetar model
PI: Rea
Abstract: On 2009 June 5 two SGR-like bursts were emitted by SGR 0418+5729
(Esposito et al. 2010, MNRAS, 405, 1787). Although this SGR showed all
the characteristics of SGRs' outbursts, a phase-coherent timing
solution over the first ∼500 d yielded no evidence for any pdot,
implying a 3σ u.l. on the B-field of <7.5 10^{12} G (Rea et al.
2010, Science in press). This is the lowest magnetic field ever
observed for a magnetar, and the first lower than the electron
critical B (~4x10^{13} G). Such a low a external dipolar B-field might
hide an internal high-B of ~10^{14} G, needed to trigger the
magnetar-like activity. The external B can be at most ~80 times the
dipolar surface B. We ask for an ACIS-S observation of 30ks in
December 2010 to keep the phase-coherence of our timing solution, and
hopefully have a final detection of the B-field of this low magnetic
field magnetar. If the B will end up to be < 10^12 Gauss, this would
pose serious difficulties on the magnetar model.


Sequence Number: 501533

Title : CHANDRA imaging of the cooling front after a high energy flare
PI: ferrigno
Abstract: The recently (Sept 19-21) observed flare of the Crab nebula above 100
MeV (ATEL 2855) is likely due to synchrotron emission of PeV electrons
injected either in the pulsar magnetosphere or close to the shock at
0.14 pc from the pulsar. If the injection happened close to the
pulsar, then high-energy particles are expected to reach the shock and
brighten it in one month time. If the flare is due to electron
injection at the shock, instabilities at the shock lead to an increase
of the injection rate which explains the observed gamma ray
brightening. At lower energies (ATELs 2856, 2858), the emission
remains stable because of longer cooling time. We expect an X-ray
counterpart of the gamma-ray flare in high resolution imaging
observation of the pulsar wind shock. With Chandra we can search for
structures/knots fading or moving (Hester et al. 2002). Follow-up
observations at later times (weeks to months) will be necessary to
follow the evolution of these structures.


Sequence Number: 501532

Title : CHANDRA imaging of the cooling front after a high energy flare
PI: ferrigno
Abstract: The recently (Sept 19-21) observed flare of the Crab nebula above 100
MeV (ATEL 2855) is likely due to synchrotron emission of PeV electrons
injected either in the pulsar magnetosphere or close to the shock at
0.14 pc from the pulsar. If the injection happened close to the
pulsar, then high-energy particles are expected to reach the shock and
brighten it in one month time. If the flare is due to electron
injection at the shock, instabilities at the shock lead to an increase
of the injection rate which explains the observed gamma ray
brightening. At lower energies (ATELs 2856, 2858), the emission
remains stable because of longer cooling time. We expect an X-ray
counterpart of the gamma-ray flare in high resolution imaging
observation of the pulsar wind shock. With Chandra we can search for
structures/knots fading or moving (Hester et al. 2002). Follow-up
observations at later times (weeks to months) will be necessary to
follow the evolution of these structures.


Sequence Number: 501531

Title : Search for new spatial structure associated with the gamma-ray
enhancement of the Crab
PI: Weisskopf
Abstract: It has just been reported (Atel 2555) that the AGILE satellite has
detected a significant variation in the emission above 100 MeV from
the environs of the Crab Nebula. A similar enhancement was seen at the
same time with the Fermi Satellite. If the source of this enhancement
is due to a new morphological feature (a new knot e.g. appearing in
the vicinity of the pulsar), then Chandra, because of its angular
resolution, is the only Observatory that can search for such a
feature.


Sequence Number: 401281

Title : Constraining the Spectrum of HLX-1 in Outburst
PI: Farrell
Abstract: HLX-1 currently provides the strongest evidence for the existence of
intermediate mass black holes. Previous observations with XMM and an
ongoing monitoring campaign with Swift have shown that it undergoes
similar spectral state transitions to stellar mass black hole
binaries, with large-scale flux variability by a factor of ~100 over
timescales of weeks to months. Our most recent Swift observation on
August 29th found that it has re-brightened and is currently at
Lx~1.3E42 erg/s, compared to Lx~3E40 erg/s only 3 weeks prior to this.
The spectrum also appears to be dominated by a soft thermal component.
We propose to observe this source with Chandra so as to constrain the
spectrum and luminosity and to search for variability that has been
detected in other states. We will thus be able to test for the
presence of a hard tail in the current spectrum, whether HLX-1 follows
the same Lx-Tin relationship as other ULXs, and whether the nH is
variable (related to outflows).


Sequence Number: 401145

Title : Measuring the spin of the black hole Cygnus X-1
PI: McClintock
Abstract: We are nearing completion of a paper on the spin of Cyg X-1. We
determine the spin by fitting the thermal accretion-disk component to
our fully relativistic disk model, while carefully modeling the
nonthermal component of emission. In this work, we have exhaustively
searched the HEASARC archives (over all time and all missions) for
useful spectra. Remarkably, there is only one suitable broadband
spectrum (a simultaneous observation by ASCA and RXTE made in 1999)
that allows us to constrain the power-law component. There is just
this single spectrum because Cyg X-1 is rarely in the required soft
state and because it has only rarely been observed with detectors
spanning the required energy interval (~1-30 keV). Cyg X-1 has just
entered the soft state. We propose to obtain 3 Chandra observations
(HETG; TE mode; 6 ks each) and will apply for simultaneous RXTE/PCA
coverage. We seek 3 observations because the quality of the soft
varies dramatically (see the references above).


Sequence Number: 401144

Title : Measuring the spin of the black hole Cygnus X-1
PI: McClintock
Abstract: We are nearing completion of a paper on the spin of Cyg X-1. We
determine the spin by fitting the thermal accretion-disk component to
our fully relativistic disk model, while carefully modeling the
nonthermal component of emission. In this work, we have exhaustively
searched the HEASARC archives (over all time and all missions) for
useful spectra. Remarkably, there is only one suitable broadband
spectrum (a simultaneous observation by ASCA and RXTE made in 1999)
that allows us to constrain the power-law component. There is just
this single spectrum because Cyg X-1 is rarely in the required soft
state and because it has only rarely been observed with detectors
spanning the required energy interval (~1-30 keV). Cyg X-1 has just
entered the soft state. We propose to obtain 3 Chandra observations
(HETG; TE mode; 6 ks each) and will apply for simultaneous RXTE/PCA
coverage. We seek 3 observations because the quality of the soft
varies dramatically (see the references above).


Sequence Number: 501371

Title : The first 'non-magnetar' soft gamma repeater
PI: Rea
Abstract: On 2009 June 5 two SGR-like bursts were emitted by a new SGR, SGR
0418+5729 (Esposito et al. 2010, MNRAS, 405, 1787), having a 9.1s spin
period. The outburst faded by a factor of ∼10 in about 200 days
when it became Sun constrained for many X-ray satellites. Although
this SGR showed all the characteristics of SGRs' outbursts, a
phase-coherent timing solution over the first ∼200 d yielded no
evidence for any pdot, implying a 3σ u.l. on the B-field of <1.5
10^{13} G. This is the lowest magnetic field ever observed for a
magnetar, and the first lower than the electron critical B (~4x10^{13}
G), posing serious problems to the magnetar model. The source became
visible again by Swift (and Chandra) a few days ago. Swift detected
the SGR (8sigma) but it showed a very low flux
(1.3x10^{-13}erg/s/cm2), too low to measure a periodicity with XRT. We
ask for an ACIS-S observation of 30ks within 15 days to have a final
detection of the B-field of this low magnetic field magnetar.


Sequence Number: 401141

Title : X-ray spectroscopy of Cir X-1 through its transition to an
exceptionally hard X-ray state
PI: D'A
Abstract: Following a long period of X-ray quiescence Cir X-1 shown a new X-ray
re-brightening from May 2010 (Atel #2608).The source has shown a
decline of its flux where the X-ray emission become dominated by
extended structures (Atel #2650, Atel #2674).A strong radio
re-brightening of the source was detected on June 24 by ATCA (Atel
#2699). The latest X-ray spectrum observed with Swift XRT (MJD
55373.47, June 26th) revealed an unusually hard spectrum (Gamma ~ 1
power-law) and absorbed by a local absorber (N_h 10^24 cm^-2).The
spectrum also shows an intense and broadened iron line at 6.4 keV
(eqw. width ~ 200 eV). We request a 20 ks Chandra/HETGS observation of
this source with these aims: to resolve the line emitting plasma and
the origin of the broadened iron line and to define the role and the
physical parameters of the plasma constituting the base of the jet
observed in the radio band.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 501369

Title : Chandra Observations of the ultra-dark GRB 100615A
PI: Levan
Abstract: A fraction of gamma-ray bursts are dark in the optical and even in the
nIR. These can be localised only using X-ray afterglows. This sample
probably includes bursts in highly obscured, extreme star forming
regions, and may originate in decidedly different environments from
optically bright bursts. Unfortunately, Swift X-ray positions are not
sufficiently precise to allow unambiguous identification of the host
galaxies, while sub-arcsecond positions from Chandra do allow for this
identification. With position in hand we can search for the host
galaxy, study its luminosity and morphology, obtain its redshift and
measure the location of the burst upon it -- these observations can
then be compared to those of optically bright bursts to derive
meaningful constraints on the burst environment. All of this
subsequent science is enabled by a modest (15 ks) Chandra
observation.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 501368

Title : Unveiling the nature of cyclic behavior in the period evolution of the
Anomalous X ray Pulsar XTE j1810-197
PI: Bernardini
Abstract: The goal of our analysis is to probe a possible long term (5 yr)
free-body precession of this neutron star for which we found several
indications based on a non-phase-connected timing analysis. Although
only 3 NS up to now have shown indication of precession, such evidence
strongly challenges our current understanding of the NS interior. The
standard picture of the outer core, in which superfluid neutrons
coexist with type II superconducting protons, requires revision. One
possibility is that protons are type I which would imply a significant
revision of our picture of the physical conditions in the NS core.
Another possibility is that the neutrons are normal in the outer core
which again affects our understanding of the physical state of NSs
core. The presence of long period modulation can shed light on the
physical properties of NS and thus help constraining its equation of
state


Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 300283

Title : The maturing of the remarkable supersoft source KT Eri
PI: Drake
Abstract: LETGS observations of KT Eri in the early SSS phase revealed dramatic
changes in C and N absorption with time that probe their abundances in
the ejected envelope and the depth-dependent nucleosynthesis of the
central engine during the blast. Now the SSS has matured, the ejected
envelope will have dissipated, and a new observation will probe the
abundances in the radiatively-driven wind and evelope and the
steady-state CN-processing. Chandra is by far best suited for this
very soft, low NH target whose spectrum extends longward of 50A. A
continuous Chandra observation will have additional value for testing
a tentative Swift detection of a 35s periodicity possibly caused by
pulsations of the white dwarf.


Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 401138

Title : X-ray Column Density Towards The Low Mass X-ray Binary 4U 1608-522
PI: Ozel
Abstract: We request a 25 ks observation of the transient low-mass X-ray binary
4U 1608-52 with Chandra HETG to measure the interstellar extinction
towards the source using absorption edges in its spectrum. 4U 1608-52
is one of our gold standard sources for the neutron star mass-radius
measurements. The column density is used to determine the distance to
the source employing a technique that makes use of red clump stars in
the field of view of the source. However, so far, only a 5ks XMM
observation has been available to measure the column density, which
results in large distance errors. Chandra observations will greatly
reduce this uncertainty by pinning down the column density with
grating observations, which, in turn, will significantly reduce the
uncertainties in the neutron star mass and radius.


Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 300277

Title : U Sco in outburst
PI: Orio
Abstract: U Sco is a VERY peculiar recurrent nova, that does not have a giant
secondary and yet is very fast. The "speed" (of ejecta and light
curve) indicates an extremely massive white dwarf. The secondary has
lost a large part of its envelope and is extremely helium enriched,
indicating an evolved system altogether - one that may be close to a
type Ia supernova explosion! X-rays are the only window to the
extremely hot underlying white dwarf and in the case of U Sco, it
would be extremely interesting to find out whether it is a massive
white dwarf, and whether it is a CO or a Ne-O-Mg white dwarf. In a new
paper on the 2006 grating observations of RS Ophiuchi, E. Behar and I
have found overwhelming evidence that RS Oph hosts a Ne-O-Mg whire
dwarf, hence is not a type I a supernova candidate. This is based on
spectral lines that appeared only for a short amount of time and have
never been observed in astronomy before (we have laboratory
confirmation).


Sequence Number: 300276

Title : The bright super-supersoft souce phase of KT Eri
PI: Drake
Abstract: Further Chandra LETGS observations will take advantage of the rare
100+ Swift XRT count/s nova, KT Eri, to probe the nature of the
explosion through the properties of the expanding enveloped of the
SSS. KT Eri is a high galactic latitude (low NH) nova that exploded on
2009 November 14. The SSS phase was detected at 13 count/s in ongoing
Swift monitoring on 2010 January 19 (day 65.7), during which the soft
X-ray flux with BB kT~20eV varied dramatically by factors of ~20 on a
timescale of ~3 hours, similar to the SSS phases of RS Oph and V458
Vul. The Swift count rate had risen steadily to 150 count/s by January
25, accompanied by variability of a factor of 2-3. A 15ks Chandra
LETGS observation obtained on January 23-24 showed a highly detailed
spectrum with numerous prominent broadened absorption features and a
clear P Cygni profile in N VI. Chandra is by far best suited for this
very soft, low NH target whose spectrum extends longward of 50A.


Sequence Number: 300275

Title : The bright super-supersoft souce phase of KT Eri
PI: Drake
Abstract: Further Chandra LETGS observations will take advantage of the rare
100+ Swift XRT count/s nova, KT Eri, to probe the nature of the
explosion through the properties of the expanding enveloped of the
SSS. KT Eri is a high galactic latitude (low NH) nova that exploded on
2009 November 14. The SSS phase was detected at 13 count/s in ongoing
Swift monitoring on 2010 January 19 (day 65.7), during which the soft
X-ray flux with BB kT~20eV varied dramatically by factors of ~20 on a
timescale of ~3 hours, similar to the SSS phases of RS Oph and V458
Vul. The Swift count rate had risen steadily to 150 count/s by January
25, accompanied by variability of a factor of 2-3. A 15ks Chandra
LETGS observation obtained on January 23-24 showed a highly detailed
spectrum with numerous prominent broadened absorption features and a
clear P Cygni profile in N VI. Chandra is by far best suited for this
very soft, low NH target whose spectrum extends longward of 50A.


Sequence Number: 300274

Title : The early SSS phase of the Classical Nova KT Eri
PI: Ness
Abstract: All novae are thought to evolve through a SuperSoft (SSS) phase,
during which the hot (kT~20-50 eV) surface of the nuclear-burning
white dwarf is visible. However, novae evolve rapidly and only 3 novae
have been observed at high spectral resolution in X-rays during the
SSS phase. Our ongoing Swift monitoring of novae in outburst has
discovered that high-amplitude variations can occur in the SSS phase
(eg RS Oph, V458 Vul). The driver is unknown, and more observations
are needed. These oscillations were first seen during 2003 Chandra
observations of V4743 Sgr where a bright SSS (40 LETG cps)
transitioned into a 0.6 cps photoionized/-excited emission line
spectrum. The nova KT Eri has entered its SSS phase (today), and Swift
is seeing high amplitude flux oscillations. A Chandra LETGS
observation will probe the spectral properties of the SSS phase at
high spectral and temporal resolution. Since all novae have behaved
differently in X-rays, a larger sample is needed.


Sequence Number: 702317

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702316

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702315

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702314

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702313

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702312

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702311

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702310

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702309

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702308

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702307

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 702306

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.


Sequence Number: 401137

Title : Chandra High Resolution Spectroscopy of the Be X-Ray binary A0535+262
PI: reynolds
Abstract: We propose to observe the Be X-ray pulsar binary 1A 0535+262 with
Chandra HETGS for 20 ks. This observations will allow us to
investigate: 1) High M_dot accretion onto a NS: These observations
will allow us to probe accretion at a high fraction of the Eddington
luminosity onto a neutron star with an accurately constrained B-field
(4e12 -- Cyclotron lines) and spin period (X-ray pulsations). 2) Disk
winds from accreting compact objects: Miller et al. (2008) have
previously obtained HETGS spectra of the black hole transient GRO
J1655-40; while Ueda et al. (2004) have obtained HETGS spectra of the
Z-source GX13+1. In both cases numerous wind absorption lines are
observed. 3) Relativistic accretion disk emission lines: Cackett et
al. (2009) have observed relativistic Fe emission from a sample of
accreting neutron star LMXBs (Z, Atoll, MSP) providing constraints on
the radius of the neutron star. This will be the definitive Chandra
observation of a Be X-ray binary.


Sequence Number: 401137

Title : Chandra High Resolution Spectroscopy of the Be X-Ray binary A0535+262
PI: reynolds
Abstract: We propose to observe the Be X-ray pulsar binary 1A 0535+262 with
Chandra HETGS for 20 ks. This observations will allow us to
investigate: 1) High M_dot accretion onto a NS: These observations
will allow us to probe accretion at a high fraction of the Eddington
luminosity onto a neutron star with an accurately constrained B-field
(4e12 -- Cyclotron lines) and spin period (X-ray pulsations). 2) Disk
winds from accreting compact objects: Miller et al. (2008) have
previously obtained HETGS spectra of the black hole transient GRO
J1655-40; while Ueda et al. (2004) have obtained HETGS spectra of the
Z-source GX13+1. In both cases numerous wind absorption lines are
observed. 3) Relativistic accretion disk emission lines: Cackett et
al. (2009) have observed relativistic Fe emission from a sample of
accreting neutron star LMXBs (Z, Atoll, MSP) providing constraints on
the radius of the neutron star. This will be the definitive Chandra
observation of a Be X-ray binary.


Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 200656

Title : X-ray Emission from V838 Mon: Stellar Merger or Ejecta-Companion
Interactions?
PI: Kastner
Abstract: The nature of the infamous 2002 outburst of V838 Mon (Bond 2007;
Tylenda et al. 2009 [T09]) remains uncertain. No nova-like "hot phase"
was observed and the presence of a B3V companion and a small cluster
implies the system is too young to harbor an accreting white dwarf.
Among the leading models for the outburst is that of a stellar merger
(Soker & Tylenda 2007 [ST07]). The merger product should become
magnetically active well after outburst (ST07), suggesting that V838
Mon should make a delayed appearance as an X-ray source. Indeed, V838
Mon went undetected by CXO in 2003 (Orio et al 2003), but when we
reobserved the object in 2008 with XMM we detected a luminous X-ray
source very near its position (Antonini et al 2009). This source may
be the spun-up merger remnant. However, V838Mon s ejecta had just
engulfed its companion at the time of our XMM observation (T09). Hence
the XMM source might be due instead to interactions between V838 Mon s
ejecta and its companion.


Sequence Number: 401125

Title : A precise position for the intermediate mass black hole candidate in
ESO 243-49
PI: Farrell
Abstract: We recently identified a ULX that provides the strongest evidence for
the existence of intermediate mass black holes (Farrell et al., 2009,
Nature, 460, 73). Previous observations with XMM and Swift gave
incompatible positions at the 1 sigma level. We obtained a 1 ks
Chandra DDT observation on 07/04/09 to resolve this discrepancy. The
ULX was not detected, so has dropped by a factor >6 in flux. By
analogy with stellar mass black holes, this might indicate a
transition into a low/hard state; such a transition has never been
observed so far from any ULX. Triggered by this result and the unique
properties of the source, we are currently preparing requests for deep
ground and space-based telescope observations, whose analysis will
require a high precision that only Chandra can provide. Even a
non-detection would be a highly significant result, as it could
indicate the ULX has undergone a transition into the low/hard state; a
phenomenon commonly observed in Galactic X-ray binaries.


Sequence Number: 401124

Title : Following the Decay of NGC 6440 X-2
PI: Heinke
Abstract: On July 28-29, our GO Chandra image of NGC 6440 discovered a 2nd
transient LMXB in outburst in the globular cluster NGC 6440 (Atel
2139). RXTE/PCA saw indications of flaring at 0.7 Hz, similar to 1 Hz
flaring from SAX J1808, which indicated propeller instabilities in the
flow (Patruno+09). We request one 5-ksec ACIS-S observation of NGC
6440 by August 14 to determine whether this transient has returned to
full quiescence (<1e31) or undergoes accretion instabilities at low
(Lx~5e32) levels, as SAX J1808 did (Campana+08). 5 ksec will give >10
cts for Lx(0.5-10)>3e32 ergs/s (either BB @0.2 keV, or PL @index~2.2
as seen by Swift for 6440 X-2).


Sequence Number: 501174

Title : Searching for the X-ray counterpart to J1622-49
PI: Rea
Abstract: A new neutron star has been recently discovered during the Parkes High
Time Resolution Universe Survey. Its radio emission is highly variable
reaching strong luminosities (up to ~35mJy). We ask for a 20ks Chandra
ACIS-I observation to characterize its X-ray counterpart, in search
for a similarly variable X-ray emission.


Sequence Number: 701973

Title : The nature of the highly-variable X-ray galaxy KUG 1259+280
PI: Watson
Abstract: We have discovered a bright, strongly variable 2XMM X-ray source which
is <2" from the nucleus of a nearby (D~100 Mpc) post-starburst galaxy
KUG 1259+280. In the XMM-Newton discovery observation the source shows
a strong flare lasting 2500 sec with a factor ~8 flux increase on a
timescale <1000 sec. Even more remarkably the X-ray spectrum is
characterized by an unprecedently soft continuum well-fit with a
power-law model with gamma=4.7. The short-timescale variability,
luminosity (Lx~3E41 erg/sec) and location close to the nucleus
suggests an NLS1 AGN, but only weak, narrow Balmer lines (consistent
with starburst) are detected in the SDSS spectrum once host galaxy
contamination is removed. Proposed Chandra observation will locate the
X-ray source to ~0.2 arcsec (~100 pc) to see if it is truly coincident
with the nucleus - importantly if it is off-nucleus this would make it
an ULX. Observation will also check for faint extended X-ray emission
and constrain variability/spectrum.


Sequence Number: 401066

Title : A precise position for the intermediate mass black hole candidate in
ESO 243-49
PI: Farrell
Abstract: While investigating the 2XMM catalogue, we identified a new ULX in the
galaxy ESO 243-49 with an unabsorbed 0.2-10 keV Lx = 1.1E42 erg/s. A
follow-up DDT observation with XMM found the spectrum had changed
significantly, ruling out multiple low-luminosity sources. The Lx is
almost an order of magnitude greater than the previous record holder,
which when taken with the steep power-law spectrum and lack of radio
emission rules out beaming. This ULX, with a conservative mass lower
limit of ~500 Msun, provides the strongest evidence for the existence
of intermediate mass black holes (Farrell et al., 2009, Nature, in
press). This object is unique, puzzling and worth following-up given
the significance of the results. We will begin monitoring this ULX
with Swift in August to search for variability. Any significant
changes in flux/spectrum will trigger requests for deep observations
with ground based telescopes. Before such observations can take place
a high precision position is required.


Sequence Number: 401065

Title : Simultaneous Chandra/ATCA observation of GRO J1655-40 in quiescence
PI: Gallo
Abstract: We have recently been awarded a very deep (12 hr) radio observation of
the quiescent X-ray binary GRO J1655-40 with the newly refurbished
Australia Telescope Compact Array (ATCA) on June 7. The goal of this
observation is to probe jet formation at the lowest possible mass
accretion rates. Beside A0620-00, which was observed simultaneously by
the VLA and Chandra in 2005 (Gallo et al. 2006, MNRAS, 370, 1351),
there is only one other quiescent black-hole system whose properties
enable us to probe jet formation at such low accretion rates, and that
is GRO J1655-40. As well as anchoring the radio:X-ray correlation at
the lowest luminosities, we should be also able to detect the radio
spectrum of a truly quiescent source for the first time. In turn, this
will allow us to compare the broadband spectral energy distribution of
a quiescent stellar mass black hole to that of the quiescent 4E+6
solar mass black hole in the Galactic Center.


Sequence Number: 200569

Title : X-ray emission from the pre-main sequence star ZCMa during a
FUOri-type outburst
PI: Stelzer
Abstract: We propose for the first X-ray spectrum of an FUOri object during
outburst. The FUOR phenomenon is associated with a sudden increase of
the accretion rate in some pre-main sequence (PMS) stars, possibly due
to changes in the magnetic field. In the first X-ray survey of FUORs
Skinner et al. (2007) have detected two of four targets. None of them
was in outburst at the time. The typical two-temperature spectrum of a
PMS star requires in the case of FUOri different absorptions for the
soft and hard components (Skinner et al. 2006). Our target ZCMa is a
young F-type FUOR. In Feb 2008 ZCMa started its so far largest
outburst, with a further enhancement ~2 weeks ago. In May 2008 we have
detected its magnetic field. Now we aim at an X-ray detection of ZCMa
in its `super-outburst'.


Sequence Number: 200568

Title : The current X-ray status of the planet bearing host star 51 Peg
PI: Schmitt
Abstract: In a 50 ksec XMM pointing we found a X-ray flux drop of >20 (compared
to ROSAT) for 51 Peg, the most famous planet-bearing host star. 51 Peg
is of very low activity and its chromospheric flux has been stable
over many years. A dramatic (downward) change in soft X-ray flux has
never been observed before in any star with the possible exception of
Alpha Cen. It is important to check how long this extremely low
activity state of 51 Peg persists. The X-ray surface flux derived from
the XMM lies more than one order of magnitude below expectation. A
possible solution is a coronal temperature change. An HRC pointing
with its larger low energy sensitivity will show if there is
undetected flux in the 0.1-0.2 keV band or if 51 Peg's corona has
almost completely disappeared from the X-ray world.


Sequence Number: 200568

Title : The current X-ray status of the planet bearing host star 51 Peg
PI: Schmitt
Abstract: In a 50 ksec XMM pointing we found a X-ray flux drop of >20 (compared
to ROSAT) for 51 Peg, the most famous planet-bearing host star. 51 Peg
is of very low activity and its chromospheric flux has been stable
over many years. A dramatic (downward) change in soft X-ray flux has
never been observed before in any star with the possible exception of
Alpha Cen. It is important to check how long this extremely low
activity state of 51 Peg persists. The X-ray surface flux derived from
the XMM lies more than one order of magnitude below expectation. A
possible solution is a coronal temperature change. An HRC pointing
with its larger low energy sensitivity will show if there is
undetected flux in the 0.1-0.2 keV band or if 51 Peg's corona has
almost completely disappeared from the X-ray world.


Sequence Number: 401051

Title : Is XTE J1701-407 Extended?
PI: Kaplan
Abstract: We recently observed the neutron star X-ray transient XTE J1701-407
with Chandra, using 1 ks of ACIS-S data for localization. However, the
Chandra data do not show a point source. Instead the source appears
extended over ~6 arcsec. We have investigated the data, consulting
with experts both at MIT and SAO, and cannot ascribe the data to
purely instrumental effects (aspect errors or pileup). The extended
X-ray emission could come from an outflow or a dust scattering halo -
both very interesting and rare phenomena. Jets allow detailed
calorimetry of the outbursts, while scattering halos lead to geometric
distances. We request a 5 ks ACIS-S subarray observation to
definitively assess the morphology, trying to discriminate between
these scenarios before the target fades into quiescence.


Sequence Number: 501152

Title : The X-ray light-curve of GRB 080307
PI: Page
Abstract: The canonical X-ray light-curve with a steep-plateau-normal decay, has
been attributed to continued energy injection; when this input ceases,
we see the steepening to the standard decay (alpha~1.3). In the case
of GRB 080307, the onset of the plateau was unusually late and,
uniquely, the decay was still continuing with a slope of <1 more than
a month after the burst. If intrinsic, this slow decay would place
severe constraints on the proposed injection model, requiring the
engine to be active for a very long time. Deep Gemini imaging reveals
a second optical source within the XRT error circle, which is a
possible source of contamination. Chandra's PSF and sensitivity will
allow us to test whether there is any contamination from this nearby
source and whether the decay has broken.


Sequence Number: 401050

Title : V Puppis: A black hole triple?
PI: Maccarone
Abstract: The nearby eclipsing binary VPup has recently been suggested on the
basis of eclipse timing residuals to have a third body with a ~5 year
orbital period and a mass of ~10 solar masses, but for which there is
no spectroscopic evidence, making it the only strong candidate for
having a black hole in a wide binary in the Galaxy. At a distance of
300 pc, this object can be studied in great detail, even if it is
extremely faint, and is the only black hole candidate with a Hipparcos
parallax distance. Past observatories showed variable X-ray emission
from this region at a level which was reasonable for Bondi accretion
from the stellar wind of the B giant in the VPup. We have recently
made ATCA observations of this region and need X-ray observations as
well, to compare the two fluxes or upper limits to determine whether
it is reasonable for such a flux ratio to come from a stellar mass
black hole, and to ensure that the past X-ray emission really is from
VPup, rather than a nearby object.


Sequence Number: 400934

Title : Locating the Ultraluminous Supersoft X-ray Source in NGC300
PI: Kong
Abstract: We propose to obtain the first Chandra image of the nearest very
luminous (Lx=1e38-1e39 erg/s) recurrent supersoft X-ray source (SSS)
currently in outburst. The source, located in NGC300, has a 5.4-hr
period and is ultraluminous in the high state. In AO-7, we obtained a
Chandra HRC-I observation to locate the position in order to search
for the optical counterpart in archival HST and VLT images. However,
the source was off with a 99% upper limit of 3.5e37 erg/s (ATel#1560).
NGC300 was observed with Swift on 2008 5/20, 6/4, and 6/19. The SSS
was clearly detected with XRT in all observations and all the source
photons are from below 0.7 keV, consistent with a SSS. The 0.2-2 keV
unabsorbed luminosity is about 1.5-2e38 erg/s (ATel#1560). If the
companion can be identified, we can set a strong constraint on the
donor and conclude whether the compact object is an IMBH. It would
also provide important information about the formation of SSS in a
black hole binary system.


Sequence Number: 400933

Title : The cold neutron star in the long-duration transient AX J1754.2-2754
PI: Keek
Abstract: As written in Atel#1575, J1754j went to quiescence after a long
outburst. The source is an ultra-compact X-ray binary. The long
outburst duration and ultra-compact nature make this source resemble
H1905+000. The current Chandra non-detection, based on a 2 ks-long
observation, shows that J1754 is very faint already given that the
long outburst duration facilitates a high neutron star crust
temperature. The low flux and the relatively high N_H forego
triggering the Wijnands et al. ToO (which is based on measuring
neutron star X-ray spectra). Instead, we propose to obtain one 30 ks
observation to search for J1754 in quiescence. In 30 ks we would reach
a flux limit of ~5E-15 erg cm-2 s-1, yielding a luminosity limit of
5E31 erg/s. A non-detection would make J1754 the second UCXB to be
very cold (after H1905) suggesting that the UC nature and hence the
composition of the accreted material is important for setting the NS
temperature and or the cooling rate.


Sequence Number: 501018

Title : An Unexpected Re-Brightening in SHB 080503: Afterglow or
mini-Supernova, 2nd Epoch
PI: Butler
Abstract: Gaining a deep understanding of the origin and nature of Short
(duration) Hard (spectrum) Gamma-ray Bursts (SHBs) is one of the last
frontiers of GRB research. We can now say almost for certain that the
progenitors of SHBs are different from those of Long-Soft GRBs (LSBs).
This is based almost entirely on observations of the host galaxies of
SHBs, which seem to be an older population than the hosts of LSBs:
whereas the 50+ hosts of LSBs appear to be underluminous star bursts,
and a handful of the bursts themselves have been directly associated
with supernova (SN) explosions. SHB hosts span the range from giant
elliptical to faint blue galaxies. A multi-wavelength campaign is
critical to ameliorate the large theoretical uncertainty as to what
types of progenitor systems --- a possible ``mini-SN'' (Li \&
Paczynski 1998) from a compact object mergers or binary WD merger
(Levan et al. 2006) --- are at the origin of SHBs.


Sequence Number: 501017

Title : An Unexpected Re-Brightening in SHB 080503: Afterglow or
mini-Supernova
PI: Butler
Abstract: Gaining a deep understanding of the origin and nature of Short
(duration) Hard (spectrum) Gamma-ray Bursts (SHBs) is one of the last
frontiers of GRB research. We can now say almost for certain that the
progenitors of SHBs are different from those of Long-Soft GRBs (LSBs).
This is based almost entirely on observations of the host galaxies of
SHBs, which seem to be an older population than the hosts of LSBs:
whereas the 50+ hosts of LSBs appear to be underluminous star bursts,
and a handful of the bursts themselves have been directly associated
with supernova (SN) explosions. SHB hosts span the range from giant
elliptical to faint blue galaxies. A multi-wavelength campaign is
critical to ameliorate the large theoretical uncertainty as to what
types of progenitor systems --- a possible ``mini-SN'' (Li \&
Paczynski 1998) from a compact object mergers or binary WD merger
(Levan et al. 2006) --- are at the origin of SHBs.


Sequence Number: 400932

Title : Chandra follow up of XTE J1719-291
PI: Sala
Abstract: XTE J1719-291 is a new, faint X-ray transient, discovered with
RXTE/PCA on March 21 (ATel#1442). PCA monitoring indicated an initial
rise followed by a delcine. Swift/XRT follow up on 30 March and April
3 provided the position with an uncertainty of 3.8 arcsec and
confirmed the decline (ATel#1451,#1467). The XRT spectrum was fit with
an absorbed powerlaw with nH=6e21cm-2 and a photon index of 3. A more
recent Swift observation on April 9 showed a re-brightening by a
factor 10 and a hardening of the spectrum (ATel#1467), with a photon
index of 2.5 and a 2-10 keV absorbed flux of 1.4e-11 erg/cm2/s. There
are no known objects in Simbad or ROSAT catalogues within the XRT
error circle. To identify the IR counterpart, we observed XTE J1719 on
April 11 in 7 bands (grizJHK) with GROND at the MPI/ESO 2.2m telescope
at La Silla. We find 13 near-infrared sources in the XRT error circle.
The transient properties are unusual, so it's unclear what kind of NIR
variability is to be expected.


Sequence Number: 701771

Title : Chandra observation of a flaring galaxy with strong optical
emission-line light echo
PI: Komossa
Abstract: We have discovered among SDSS-DR6, in Dec. 2007, a galaxy which is
unique in showing super-strong high-ionization iron lines and very
unusual double-peaked Balmer lines which are fading away, but have not
yet disappeared. The high degree of line ionization implies that we
see the light-echo of an (unobserved) EUV-X-ray flare. We have
confirmed, with optical ToO photometry on Jan. 1, 2008 the low-energy
tail of this flare in the optical and NIR. Only a few X-ray flaring
galaxies are known. This is the first time we have seen such a broad
line and continuum response. With Chandra, we will for the first time
detect the actual X-rays from this flare, characterize the X-ray
emission, locate the flare within 1 kpc of the nucleus, and test the
favored scenario - tidal disruption of a star - before the flare has
faded away. Depending on the measured source's X-ray brightness, we
will then consider X-ray monitoring to map the emission-line changes
in response to the X-ray fading.


Sequence Number: 400931

Title : A rare transient in M81: a merger event?
PI: Jonker
Abstract: A recently discovered optical transient (OT) in M81 (atel #1330) can
not be explained by a known transient event, it is a very good merger
candidate (NS-NS, BH-NS). Distinguishing properties are: decay rate is
too fast for a NOVA, optical brightness is too low for a SN (MV=-7.3),
the K-band magnitude and NIR colors rule out a foreground flaring
M-dwarf, the source is too bright for an transient X-ray binary. We
searched the Chandra archive for the presence of an X-ray source. None
was found even after stacking all the ACIS data. A transient X-ray
source was observed on 2000-05-07 in Chandra OBS ID 735 close to the
position of the OT. However, the distance to the position of the OT
was 2.8 arcsec which is too much for the two events to come from the
same source. The optical decay time matches the predicted decay time
for a merger event (Sylvestre 2003). If this OT is a merger event,
X-rays are predicted to be emitted due to either fall back or
radio-active decay of ejected material.


Sequence Number: 501014

Title : Chandra observations of a nearby supernova
PI: Roelofs
Abstract: We propose Chandra observations of the nearby type-Ia supernova
SN2007on to characterize its X-ray emission, which will help us
constrain the nature of the progenitor. We ask for an initial 40ks
which will enable us to put useful constraints on its X-ray flux.


Sequence Number: 501014

Title : Chandra observations of a nearby supernova
PI: Roelofs
Abstract: We propose Chandra observations of the nearby type-Ia supernova
SN2007on to characterize its X-ray emission, which will help us
constrain the nature of the progenitor. We ask for an initial 40ks
which will enable us to put useful constraints on its X-ray flux.


Sequence Number: 200526

Title : The physics of flares in young stellar objects
PI: Micela
Abstract: Flares are the most extreme manifestation of stellar activity.
Magnetic reconnection produces fast electrons that hit the stellar
surface to produce chromospheric material evaporation. Non-thermal
heating shows up as impulsive flares in optical and hard X-rays, and
evaporation as longer soft X-ray flares. Multi-band observations
covering thermal and non-thermal components are essential to
understand the physics of flaring. The CoRoT space telescope will
continuously observe the star forming region NGC2264 for 20 days in
March 2008 in the optical with unprecedented photometric precision and
with a temporal resolution of 10s of sec, ideal for the detection of
impulsive events. We ask for two 100ksec observations in the two most
populated cluster regions during the CoRoT observation to
simultaneously study the non-thermal (CoRoT) and the thermal (Chandra)
components of flares. 100s of flaring sources have already been
detected in a single ACIS field in NGC2264 (Flaccomio et al. 2006).


Sequence Number: 200526

Title : The physics of flares in young stellar objects
PI: Micela
Abstract: Flares are the most extreme manifestation of stellar activity.
Magnetic reconnection produces fast electrons that hit the stellar
surface to produce chromospheric material evaporation. Non-thermal
heating shows up as impulsive flares in optical and hard X-rays, and
evaporation as longer soft X-ray flares. Multi-band observations
covering thermal and non-thermal components are essential to
understand the physics of flaring. The CoRoT space telescope will
continuously observe the star forming region NGC2264 for 20 days in
March 2008 in the optical with unprecedented photometric precision and
with a temporal resolution of 10s of sec, ideal for the detection of
impulsive events. We ask for two 100ksec observations in the two most
populated cluster regions during the CoRoT observation to
simultaneously study the non-thermal (CoRoT) and the thermal (Chandra)
components of flares. 100s of flaring sources have already been
detected in a single ACIS field in NGC2264 (Flaccomio et al. 2006).


Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst,
we expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance
of 2.5 AU, 1.0 AU more than any other comet observed with Chandra, it
will not only allow us to probe the solar wind at a far distance, but
it will also provide an unprecedented viewing geometry - we will see
the comet from almost the direction as the incident solar wind. Thus,
by utilizing the high spatial resolution of Chandra, it should be
possible to explore the spectral evolution across the face of the
coma. The ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.


Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst,
we expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance
of 2.5 AU, 1.0 AU more than any other comet observed with Chandra, it
will not only allow us to probe the solar wind at a far distance, but
it will also provide an unprecedented viewing geometry - we will see
the comet from almost the direction as the incident solar wind. Thus,
by utilizing the high spatial resolution of Chandra, it should be
possible to explore the spectral evolution across the face of the
coma. The ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.


Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst,
we expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance
of 2.5 AU, 1.0 AU more than any other comet observed with Chandra, it
will not only allow us to probe the solar wind at a far distance, but
it will also provide an unprecedented viewing geometry - we will see
the comet from almost the direction as the incident solar wind. Thus,
by utilizing the high spatial resolution of Chandra, it should be
possible to explore the spectral evolution across the face of the
coma. The ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 400928

Title : Which M15 X-ray Source Brightened?
PI: Heinke
Abstract: We have recently discovered, in archival data, a very faint X-ray
transient in M15 (2004 and 1994 outbursts at ~5e33 ergs/s), in
addition to the two known bright LMXBs. We have just become aware that
the RXTE ASM has recently (June-July) registered an outburst from M15
(=X2127+119), with countrates reaching 4 times normal. 3-4 smaller
outbursts have been seen by RXTE, but this is the brightest yet seen.
Both M15 persistent LMXBs show stable mass transfer. We suspect that
the recent outburst may be due to a third source, possibly the newly
identified transient, or perhaps another source. We request a short
10-ksec HRC-I observation of M15 sometime over the next 10 days to
identify if another X-ray source, besides the two bright LMXBs, is
responsible for the recent brightening of M15. This will give at least
5 counts from all sources with Lx(0.5-10)>2.6e32 ergs/s (for photon
index 1.7).


Sequence Number: 501009

Title : A radio and X-ray study of Type Ic SN2007gr at < 10 Mpc
PI: Soderberg
Abstract: The new Type Ic SN2007gr at just 10 Mpc was spectroscopically
identified on Aug 16 2007 at an estimated age of a few days since
explosion. Our radio follow-up on Aug 17 shows a radio transient
coincident with the optical position. Simultaneous radio (synchrotron)
and X-ray (synchrotron,thermal,and/or IC) observations of SNe Ibc
trace the interaction of the fastest ejecta with the circumstellar
material and have been limited to just a handful of events to date.
The combination of radio and X-ray data breaks model degeneracies and
enables the parameters of the fastest ejecta to be revealed.
Extrapolating the optically thin radio emission as nu^-0.7 to the
X-ray band we expect at a count rate of roughly 0.0005 cps. We
therefore request 20 ksec of DDT within 1-2 weeks for our radio/X-ray
study of this very nearby SN.


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 400691

Title : RFO with Chandra of the newly discovered Millisecond X-ray Pulsar
(MsXP) SWIFT J1756.9-2508
PI: Di Salvo
Abstract: According to the recycling scenario MsXPs are the progenitors of radio
ms pulsars.The recent discovery of the 5.5ms pulsar in the X-ray
transient SWIFT J1756.9-2508(ATEL #1108)brought to 8 the number of
sources of this class.Timing techniques applied to high temporal
resolution data allows the direct measurement of the rotational
behavior of the compact object under the effect of accretion,leading
to an unique opportunity to answer to the long lasting dispute about
accretion models for fast rotators(Burderi 2006,ApJL,653,133;Burderi
2007,ApJ,657,961(BD);Papitto 2007,MNRAS,375,971).However timing
analysis is able to produce reliable results only when an accurate
position of the source is known(BD).The excellent Chandra spatial
resolution will provide an unique accuracy on this key
parameter(Krauss 2005,ApJ,627,910(KR))to further investigate the
rotational behavior of these objects.Chandra will also give us the
possibility to study a high energy resolution spectrum of this
source.


Sequence Number: 400690

Title : Observing flaring activity in the new source SWIFT J195509.6+261406
PI: KANBACH
Abstract: SWIFT/BAT triggered on a new source on 10 June, 2007 20:52:26 UTC
(GCN# 6489, Pagani et al.). The reported position was promptly
observed in optical light and, after some delay, with the XRT. Bright
short optical outbursts (10s timescales, amplitudes >3 mag) were
discovered in the first hour after the trigger and again during the
night June 11-12, 2007 (GCN# 6492,6508, Stefanescu et al.). SWIFT/XRT
confirmed the position of the optical counterpart and the flaring
behaviour (amplitudes up to 25 mCrab). We propose to perform CXO-HETG
spectroscopy of the source to determine the emission process through
the spectrum, and thus the nature of this object. It could be a fast,
giant X-ray transient, SGR or AXP, or a thermonuclear X-ray burster.


Sequence Number: 400689

Title : X-ray jets in CirX-1
PI: Jonker
Abstract: CirX-1 is a neutron star (Tennant et al 1986a,b). The X-ray and radio
flux of CirX-1 have gradually decayed over the last few years.
Recently the radio flux has increased dramatically (ATel 985). The
source has returned to the low X-ray-flux high radio-flux state as
found in the 1970-80ties. On March 6 Fender observed a radio jet using
ATCA at 2" from the core. Interestingly, the position angle of the
radio jet has changed. The large radio flares suggest that major
ejection events take place. We propose a 50 ksec HRC-I observation to
take advantage of the current favorable source/jet count rate ratio to
search for an X-ray counterpart to the new radio jet emission. We
assumed that the X-ray flux and spectrum of a jet is the same as the
X-ray jet observed in XTE J1550-564. For the X-ray flux of CirX-1 we
took the value from our SWIFT-XRT ToO observation of March 19. We
simulated with ChaRT/marx that even a jet placed at a distance of
0.75" is detectable.


Sequence Number: 400688

Title : X-ray jets in CirX-1
PI: Jonker
Abstract: CirX-1 is a neutron star (Tennant et al 1986a,b). The X-ray and radio
flux of CirX-1 have gradually decayed over the last few years.
Recently the radio flux has increased dramatically (ATel 985). The
source has returned to the low X-ray-flux high radio-flux state as
found in the 1970-80ties. On March 6 Fender observed a radio jet using
ATCA at 2" from the core. Interestingly, the position angle of the
radio jet has changed. The large radio flares suggest that major
ejection events take place. We propose a 50 ksec HRC-I observation to
take advantage of the current favorable source/jet count rate ratio to
search for an X-ray counterpart to the new radio jet emission. We
assumed that the X-ray flux and spectrum of a jet is the same as the
X-ray jet observed in XTE J1550-564. For the X-ray flux of CirX-1 we
took the value from our SWIFT-XRT ToO observation of March 19. We
simulated with ChaRT/marx that even a jet placed at a distance of
0.75" is detectable.


Sequence Number: 600649

Title : Constraining the Geometry and Energetics of the Exceptionally
Energetic GRB070125
PI: Frail
Abstract: The IPN and Swift-localized GRB070125, the brightest radio afterglow
seen in almost four years, exhibits a steep spectrum from GHz
frequencies up to ~1 mm, indicating a dense local environment (n >~
100 cm^-3) and an extreme isotropic-equivalent afterglow energy
(~10^54 erg). Depending solely on the angle of collimation (i.e. "jet
opening angle") derived for this burst, it may easily become the
highest-energy release GRB seen to date, straining the capacity of
collapsar models and sounding the death knell for the "standard energy
reservoir" of GRBs (Frail et al., ApJ, 562, 2001). We have an
extensive set of optical and radio data for this burst that show a
likely jet break at t~5 days; at this same epoch, the X-ray afterglow
fades below the detection limit of Swift. We request a single 30-ksec
observation with Chandra to distinguish jet-break from no-break models
for the X-ray emission, and therefore to enable measurement of the
prompt and afterglow energies for this remarkable event.


Sequence Number: 500822

Title : Localization of SN 2005kd
PI: Pooley
Abstract: We propose to observe the Type IIn (narrow emission line) SN 2005kd. A
recent optical spectrum shows it is similar to the extremely X-ray
luminous SN 1988Z (in fact, it has a higher eq. width of H\alpha than
88Z did at a similar epoch). A recent Swift observation detected
emission consistent with the SN at Lx = 1.4e41 erg/s (d=61.5 Mpc).
Because the SN is only 5" from the nucleus of its host galaxy, and
because there may be ULXs also present in the host, we would like to
determine the amount of "contamination" in the Swift emission to the
10% level. In 3ks, we will detect ~75 counts from 05kd, and ~7 counts
from something that's 10% the flux. This will allow a conclusive
association of the Swift source with the SN, as well as provide a
measure of possible contaminating sources. We also plan on proposing
for a deep XMM observation to obtain a high quality spectrum (it will
be visible in a few weeks), and in this case as well, a measure of
contamination will be invaluable.


Sequence Number: 701583

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.


Sequence Number: 701582

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.


Sequence Number: 701581

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.


Sequence Number: 701580

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.


Sequence Number: 701579

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.


Sequence Number: 701578

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.


Sequence Number: 701577

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.


Sequence Number: 701576

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.


Sequence Number: 500821

Title : Confirmation of a new Isolated Neutron Star in the ROSAT All Sky
Survey
PI: Rutledge
Abstract: The 7 known X-ray dim isolated neutron stars (INSs) were all
discovered from the ROSAT all-sky survey between 1995 and 1999. We may
have discovered an important one: the first INS in the halo. 1RXS
J1412+7922 is important because: (1) its blackbody spectrum is hotter
than any known INS (235+/-45 eV; compared with 118+/-13 for the next
hottest); (2) its low flux (0.05 PSPC c/s) and high temperature make
it the most distant known INS (8.2 kpc, compared with 2.3 kpc for RX
J0806-4123; the remaining six are <1 kpc); and (3) its high galactic
latitude gives it a galactocentric position (R_c=13.4, z=4.9 kpc) in
the galactic halo. J1412 cannot be powered by accretion (no ISM in the
halo); if cooling, it must be <1e6 yr old, giving a velocity of >4900
km/sec (from the Galactic plane), the highest ever observed.
Otherwise, a cooling time of >1e7 yrs is required, the longest ever
observed.


Sequence Number: 500820

Title : Repudiation or Confirmation of an Enormous Glitch in a Magnetar
PI: Woods
Abstract: On Sep 21, 2006, a bright X-ray burst was recorded (GCN 5581) from the
newly discovered AXP CXO J1647-45. The burst was accompanied by a
large flux increase, spectral hardening, a dramatic pulse profile
change, and a reported glitch of dnu/nu ~1e-4 (ATEL 932) whose
amplitude is unprecedented for any neutron star. Using 4 CXO
observations between 9/27 and 10/28, we have been able to track the
spectral changes, pulse morphology evolution, and provide the first
measurement of the spin-down rate and thus magnetic field strength of
CXO J1647-45 (ATEL 929). Further analysis of all available X-ray data
has brought into question the reality of the reported glitch. The
parameters of this glitch factor heavily into the physical
interpretation of the outburst and in general, our understanding of
the internal structure of magnetars. We are requesting one additional
observation to extend our phase-coherent timing solution to confirm
the measured spin-down rate and better anchor our ephemeris.


Sequence Number: 500817

Title : Accurate position measurement of the Isolated Neutron Star RBS1774
PI: Zane
Abstract: We request a 1ks DDT pointing of the Isolated Neutron Star (INS)
RBS1774, to obtain an accurate determination of the X-ray position.
Position measurements of INSs are of paramount importance for an exact
identification of the optical counterpart: it provides vital
information on the SED, on the cause of the X-ray emission, and, over
a longer term, paves the way to the determination of proper motion and
distance; providing crucial informations on the INS surface
temperature and magnetic field distribution, kick velocity and
energetics, which are still largely unknown. We have recently observed
the RBS1774 field with the VLT, the Magellan telescope and with Keck.
Several sources appear in the XMM error box of the INS and even more
are expected to be detected by deeper VLT images, just requested, that
will push the detection limit down to a V=28. A Chandra HRC-I accurate
position is necessary to reliably determine RBS1774 counterpart.


Sequence Number: 200460

Title : A(nother) Star is Born: the Early Evolution of a Pre-main Sequence
Accretion Burst
PI: Kastner
Abstract: Accretion processes produce X-ray emission in a wide variety of
astrophysical environments, yet the link between pre-main sequence
(PMS) star accretion and X-ray emission remains tenuous at best.
Undoubtedly the most convincing example of accretion-driven PMS X-ray
emission is that of V1647 Ori; Chandra observations obtained over the
(two-year) duration of the optical/IR outburst of this PMS star
revealed that its X-ray flux and hardness closely tracked the dramatic
rise and subsequent decline of its accretion luminosity (Kastner et
al. 2004, Nature, 430, 429 and 2006, ApJ, 648, L43). These results for
V1647 Ori suggest that X-ray emission from erupting low-mass, PMS
stars is diagnostic of the degree of star-disk magnetic field
reorganization during major ("FUor"- or "EXor"-type) accretion events.
Prompt post-outburst observations of additional erupting PMS stars are
required to test this hypothesis.


Sequence Number: 500816

Title : The Extreme Supernova 2006gy
PI: Pooley
Abstract: We propose to observe the Type IIn (narrow emission line) SN 2006gy in
NGC 1260. Its optical spectrum (CBET/IAUC submitted) show it is
similar to the extremely X-ray luminous SN 1988Z, which was observed
at Lx=10^41 erg/s at an age of 6.5 yr. It is unknown what the
early-time (first few weeks to months) Lx of such a SN would be. Past
attempts at early X-ray detections (2005bx, 2005db) have given only
upper limits (but follow-ups have been approved), but the class is
likely not homogenous. The extreme optical luminosity (M_V = -22)
makes this SN stand out even among the IIn's (an already unusual class
of objects). The astrometry will be crucial to resolving the SN from
possible nuclear activity. Two X-ray sources within 2.5 arcmin of
2006gy (found in ObsID 5597) have 2MASS counterparts. They have fluxes
of 5.1e-15 and 2.1e-14 (cgs). Our request of 30 ks is based on
localizing these sources well enough (getting 25-30 cts) to achieve
~<0.2" X-ray/2MASS astrometry.


Sequence Number: 500815

Title : X-Ray Emission from the Type Ib SN 2006jc
PI: Immler
Abstract: An X-ray source is detected at the position of the SN in a 3.4 ks
Swift XRT obs from 2006-10-13 16:10 UT with a flux and lum of
1.0+/-0.4 E-13 ergs/cm/cm/s and 6.7+/-2.7 E39 ergs/s (0.2-10 keV). The
UV-V colors are extremely blue, similar to the X-ray bright SN IIP
2006bp. The Swift UVOT data show that the SN is very bright in the opt
and especially in the UV (ATel 916), likely a result of the shock
interaction with dense CSM, confirming that the X-rays are due to the
SN. Due to the large PSF of the XRT (18 HPD), and an offset of the SN
of 11" W and 7" S of the host galaxy, UGC 4904, XRT data do not allow
us to unambiguously associate the X-ray source with the SN, even at
higher photon statistics. No further Swift obs will be obtained due to
Sun angle constraints. The RASS shows no X-ray source at the position
of the host galaxy. Therefore, the association of the X-ray source
with the SN is strong and the Chandra obs could establish SNe Ib, for
the first time, as X-ray sources.


Sequence Number: 500814

Title : Monitoring a Recovering AXP and Measuring Pdot
PI: Kaspi
Abstract: Anomalous X-ray Pulsar (AXP) outbursts are rare, occuring roughly once
per decade per src, and offer rare opportunities to constrain the
poorly understood physics of magnetars. Recently AXP CXO
164710.2-455216.9 went into outburst and we were granted 3 ToO obs
with CXO. These obs together, via phase-coherent timing, set the best
constraint on the unknown Pdot, which implies magnetic field (3sig)
<2e14 G. This is low for a magnetar but not yet a problem. We request
1 more 25 ks DDT obs of AXP CXO 164710.2-455216.9. This obs will
continue to monitor it back to quiescence to distinguish between
proposed recovery models, and, importantly, if scheduled near Oct 30,
will either detect or put an unprecedented upper limit on Pdot, via
phase connection with previous CXO ToO obs. If no Pdot is detected, we
will constrain B<5e13G (3sig), lower than for any other known magnetar
(lowest known 6e13G), and perplexingly below B measured for some
ordinary, non-magnetar neutron stars.


Sequence Number: 400680

Title : Probing the true nature of the microquasar candidate LS I +61 303
PI: Perez-Torres
Abstract: The radio-emitting x-ray binary LSI +61 303 has been recently detected
at TeV energies. Two scenarios have been proposed to account for this
high-energy emission, namely an accretion/jet mechanism (microquasar),
and an interacting pulsar wind model. We propose to observe LSI +61
303 with Chandra as part of a multi-wavelength campaign that includes
simultaneous observations with MAGIC (gamma-rays), MERLIN (radio), and
Calar Alto (infra-red). (Those observations have been approved for the
nights of the 25 and 26 October 2006.) The proposed observations will
be the first such simultaneous, multiwavelength effort on this object,
and the geometrical, spectral and temporal features of its radio
emission will be studied and correlated with those in the infra-red,
X-ray and, TeV regimes. The results will help to elucidate the true
nature of LS I +61 303 and the acceleration mechanisms that produce
the high energy emission.


Sequence Number: 600607

Title : Accurate X-ray position of a possible >10^41 erg/s ULX: evidence for
an intermediate-mass black hole?
PI: Miniutti
Abstract: We have detected with XMM-Newton an off-nuclear ULX candidate in the
D25 ellipse of a spiral galaxy at 90 Mpc. If at 90 Mpc, its 0.5-10 keV
luminosity is 1.3x10^41 erg/s, the most luminous ULX ever detected.
The probability of it being a background AGN is very low based on
standard logN-logS (<0.7%) and even lower if the minimum X-ray to
Optical flux ratio (>60) is considered. The only available HST image
shows several possible counteparts in the XMM error box. We request a
7ks Chandra ACIS-S exposure to measure the X-ray position with high
accuracy, which will allow us to identify the counterpart (if any)
from HST+Chandra and to organize the optimal follow-up strategy. The
Chandra obs by itself may exclude that the ULX is a background AGN if
the HST counterpart is identified, allowing us to compute a precise
X-ra to Optical ratio which, if > 100 (as for the large majority of
possible counterparts), would exclude the AGN hypothesis.


Sequence Number: 400561

Title : Is PSR B1931+24 the golden source for the accretion regimes testing?
PI: Rea
Abstract: Very recently the discovery of an intermittent radio pulsar was
reported on Science (Kramer et al.2006,astro-ph/0604605). PSR B1931+24
has the surprising peculiarity of being a 813ms radio-pulsar for ~5d
and being radio quiet for the following 25-35d, periodically. The
pulsar spin slows down 50% faster when the pulsar is on than when is
off. The ~30d periodicity and the weird spin-down behaviour of this
radio activity remind what is expected for a pulsar in a binary system
spinning near the equilibrium period in an eccentric ~30d orbit: at
the apastron the low wind accretion rate allows the radio pulsar
regime, while at the periastron the neutron star is radio-quiet
because accreting and emitting in the X-rays. This might be the
linking object between the X-ray binaries and the radio pulsar
binaries, a golden source for finally testing the accretion regimes.


Sequence Number: 100067

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.


Sequence Number: 100066

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.


Sequence Number: 100065

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.


Sequence Number: 100064

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.


Sequence Number: 100063

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.


Sequence Number: 300179

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.


Sequence Number: 300178

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.


Sequence Number: 300177

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.


Sequence Number: 300172

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985 It was observed by EXOSAT. It's outburst commenced on Jan. 26
(IAUC 4030, 4031, 4036). EXOSAT observed RS Oph between 18h00 and
23h00 UT on 1985 Mar. 22. Preliminary analysis indicated that the
x-ray spectrum was soft and absorbed. Fits to a thermal bremsstrahlung
model yielded a temperature of 0.75 keV and an absorbing column
density of ~ 10**21 atoms cm**-2. The flux at Earth in the 0.1-6.0-keV
band was estimated to be 4 x 10**-10 erg cm-**2 s**-1. This was taken
from an IAU Circular by Cordova and Mason in 1985. It has an extremely
rapid decline in Xrays which are probably caused by a shock moving
through a red giant atmosphere.


Sequence Number: 500693

Title : Chandra observation of the Type Ia SN 2005ke
PI: Immler
Abstract: The longest Swift obs. obtained to date (258-ksec) on a SN gives
evidence that the Type Ia SN 2005ke has been detected in X-rays, at a
low level of significance (3-3.5 sigma, CBET 387). See
http://lheawww.gsfc.nasa.gov/users/immler/SN2005ke/Immler_fig1.jpg for
Swift UV and XRT X-ray image. No SN Ia has ever been detected in
X-rays. The Swift UVOT UV lightcurve
http://lheawww.gsfc.nasa.gov/users/immler/SN2005ke/Immler_fig3b.jpg
shows a UV excess starting around 35d after the explosion with respect
to SN Ia lightcurve templates, coinciding with the onset of X-ray
emission. The detection of UV excess is independent confirmation that
the X-rays are from the interaction of the SN shock with CSM as the UV
emission is due to the Mg II emission line at 280 nm. We request a
15-ksec Chandra ACIS-S observation of the nearby (20.7 Mpc) Type Ia SN
2005ke to unambigiously associate the detected Swift X-ray source with
the SN.


Sequence Number: 500692

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.


Sequence Number: 500691

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.


Sequence Number: 500690

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.


Sequence Number: 500689

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.


Sequence Number: 400559

Title : Searching for the optical/IR counterpart of the transient X-ray pulsar
Swift J1626.6-5156
PI: Homan
Abstract: The transient 15.3 sec X-ray pulsar Swift J1626.6-5156 was discovered
late 2005. It shares some properties with anomalous X-ray pulsars,but
is most likely a 'normal' X-ray pulsar with some unusual properties.
Determining the nature of the companion star could shed light on the
mode of accretion (disk vs. wind), which in turn might help explain
some of the unusual properties. Recent IR observations seem to rule
out a HMXB as the optical counterpart of the source (ATel 713).
Further attempts at identifying the optical counterpart are hampered
by the uncertainty in the position of the source. The most accurate
position has 90% an error circle of ~3.5 arcseconds (ATel 688).
However, reliable counterparts to other X-ray sources have been found
outside Swift/XRT error circles before (see e.g. Atel 712). The main
goal of the proposed short HRC observation is to improve on the
Swift/XRT position and thereby provide better constraints for
identifying a possible optical/IR counterpart.


Sequence Number: 400558

Title : Eruptive Behavior in HD 109962: A compact object interacting with a W
UMa system?
PI: Walter
Abstract: HD 109962 (vsnet-alert 8794) is in outburst. It is a 0.89 day W UMa
eclipsing binary. It is not a known X-ray source. What makes HD 109962
of interest is that it shows ~0.8 mag outbursts of ~40 day duration
about once a year (see http://ar.geocities.com/varsao/NSV_19448.htm).
The latest outburst began about 12/26/05. A red spectrum on Jan 13.2
shows a P Cygni H-alpha line, indicative of wind emission. The blue
spectrum on Jan 16.2 is astounding. Superposed on a normal F2V
spectrum is a large He II 4686 emission line (EW = -2.9 A). He II 4686
requires a source of highly ionizing radiation. It is certainly not
normally seen in F2V stars or W UMa systems. The ~periodic nature of
the outbursts suggests a model akin to Cir X-1, with a compact object
on a highly elliptical orbit that penetrates the wind from the W UMa
system. It should be a bright X-ray source during the outburst. If so,
followup observations will provide a unique probe of the wind of a
contact binary system.


Sequence Number: 500685

Title : Investigating Circumstellar Interaction in the type Ia SN 2005gj
PI: Pooley
Abstract: The supernova 2005gj was just reported (CBET 302) to display the
signatures of circumstellar interaction. This is only the second
detection of hydrogen in the optical spectrum of a type Ia supernova.
The interaction of SN ejecta with surrounding material should give
rise to X-ray emission, as it does in core-collapse SNe. An
observation with Chandra will measure the luminosity, thus determining
the strength of the interaction. Very little is known about the
progenitors of Ia SNe. Because the X-rays are a great probe of the
circumstellar material around a SN, this Chandra observation could
shed important light on the progenitor system.


Sequence Number: 800555

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 300171

Title : HETGS Observation of a Transient Hard X-ray Symbiotic Binary
PI: Sokoloski
Abstract: RT Cru is one of a subset of particularly active symbiotic stars (SS;
white dwarfs accreting from the wind of red giants) characterized by
rapid optical flickering, and in some cases jets and recurrent nova
explosions. The recent detection of RT Cru with INTEGRAL (ATels 519,
528, and 591) indicates that during outburst, it also produces the
hardest X-ray emission of any known SS. In August, RT Cru was observed
with the Swift XRT for 4.7 ks. The XRT observation revealed several
emission-line complexes, a possible broad soft component, and hints of
continuum emission. The line blends could be due to Si, Ca, and Ar.
But Ca and Ar are not strong in nova spectra, and large blue- or
red-shifts are not expected in RT Cru. We request a 50-ks HETGS
observation to resolve and identify the emission lines and any
absorption features, and to isolate the continuum. We will also search
for extended jet structure in the 0th-order spot. This observation
should produce ~2000 counts in the MEG.


Sequence Number: 200372

Title : HRC Imaging of the `Fainted' Primary of the Alpha Centauri System
PI: Ayres
Abstract: The famous Alpha Centauri binary (G2V+K1V) has been regularly observed
in X-rays since first resolved by Einstein 25 years ago, later by
ROSAT/HRI, and more recently by XMM. The latest EPIC-pn imaging
uncovered an extremely odd result: solar twin Alp Cen A has nearly
disappeared in X-rays. This behavior had not been encountered in the
previous quarter century of X-ray work on the system, and is quite
unlike anything ever seen on the Sun, except perhaps the curious
18th-century "Maunder minimum," when sunspots vanished from the solar
disk for decades at a time, and coronal activity likely was severely
depressed; although, of course, we don't have any X-ray observations
from then to confirm the true coronal behavior. The AB orbit now has
closed below the resolution of EPIC, although still is easy for
Chandra to separate. I therefore propose to continue the crucial X-ray
time series on this important solar analog using Chandra's HRC-I.


Sequence Number: 200371

Title : HRC Imaging of the `Fainted' Primary of the Alpha Centauri System
PI: Ayres
Abstract: The famous Alpha Centauri binary (G2V+K1V) has been regularly observed
in X-rays since first resolved by Einstein 25 years ago, later by
ROSAT/HRI, and more recently by XMM. The latest EPIC-pn imaging
uncovered an extremely odd result: solar twin Alp Cen A has nearly
disappeared in X-rays. This behavior had not been encountered in the
previous quarter century of X-ray work on the system, and is quite
unlike anything ever seen on the Sun, except perhaps the curious
18th-century "Maunder minimum," when sunspots vanished from the solar
disk for decades at a time, and coronal activity likely was severely
depressed; although, of course, we don't have any X-ray observations
from then to confirm the true coronal behavior. The AB orbit now has
closed below the resolution of EPIC, although still is easy for
Chandra to separate. I therefore propose to continue the crucial X-ray
time series on this important solar analog using Chandra's HRC-I.


Sequence Number: 200370

Title : HRC Imaging of the `Fainted' Primary of the Alpha Centauri System
PI: Ayres
Abstract: The famous Alpha Centauri binary (G2V+K1V) has been regularly observed
in X-rays since first resolved by Einstein 25 years ago, later by
ROSAT/HRI, and more recently by XMM. The latest EPIC-pn imaging
uncovered an extremely odd result: solar twin Alp Cen A has nearly
disappeared in X-rays. This behavior had not been encountered in the
previous quarter century of X-ray work on the system, and is quite
unlike anything ever seen on the Sun, except perhaps the curious
18th-century "Maunder minimum," when sunspots vanished from the solar
disk for decades at a time, and coronal activity likely was severely
depressed; although, of course, we don't have any X-ray observations
from then to confirm the true coronal behavior. The AB orbit now has
closed below the resolution of EPIC, although still is easy for
Chandra to separate. I therefore propose to continue the crucial X-ray
time series on this important solar analog using Chandra's HRC-I.


Sequence Number: 400472

Title : Confirmation of the Fading Afterglow From the Short Burst GRB 050709
PI: Frail
Abstract: Seven years after the afterglow detections that revolutionized studies
of the long/soft gamma-ray bursts (LSBs), not even one afterglow of a
short/hard GRB (SHB) has been seen. Theoretical calculations suggest
that SHB afterglows will be much fainter than LSB afterglows, faint
enough that ground-based detections should probably not be expected.
Deep Chandra observations, on the other hand, if made within days of
the burst, should be able to find the X-ray afterglow. This appears to
be the case with the recent GRB050709 in which Chandra observations
conducted 2.5 days after the burst detected a source (GCN 3585). Its
flux is consistent with a t^-1.4 power-law decay from the afterglow
peak observed by the HETE SXC at 100 s after the burst. Spectroscopy
undertaken with Gemini of an optical source near the Chandra position
(GCN 3589) yields a redshift z=0.16. The SHB mystery will be solved if
the Chandra source fades away in time.


Sequence Number: 400470

Title : Search for X-Ray Jets from a Millisecond Pulsar
PI: Chakrabarty
Abstract: The nearby (2.5 kpc) millisecond X-ray pulsar SAX J1808.4-3658 is in
outburst as of June 1 (ATEL 505). In its 1998 outburst, the source
showed both radio emission and an infrared excess about 15-20 days
after the outburst peak, suggestive of synchrotron emission from a jet
(Wang et al. 2001, ApJ, 563, L61). Very few NS jet sources are known
(Sco X-1, as well as SS433 and Cir X-1 if they are NSs), and this
source provides the first opportunity to link jet emission to a pulsar
with known magnetic field strength. At a source distance of only 2.5
kpc (in't Zand et al. 2001, A&A, 372, 916), the HRC angular resolution
of 0.4 arcsec corresponds to a separation of 6 light-days at the
pulsar, providing excellent angular sensitivity to a relativistic
ejection.


Sequence Number: 400469

Title : Outburst spectroscopy of the closest accretion-powered millisecond
pulsar
PI: Galloway
Abstract: The visibility of persistent pulsations in accretion-powered
millisecond pulsars (in contrast to other LMXBs) suggests that surface
spectral features might also be more easily detectable. SAX
J1808.4-3658 is the closest of the three MSPs with H-rich donors;
three more are ultracompact and likely accrete primarily He from
degenerate companions. Surface spectral features may arise from
freshly accreted material and the products of spallation reactions,
the rate of which may be greater for H-rich accretors (L. Bildsten,
pers. comm.). Although no high signal-to-noise HETGS spectrum of SAX
J1808.4-3658 has been taken, an opportunity to obtain such a spectrum
has arisen with the early detection of a new outburst on 1 June (ATel
#505). We propose to observe the source with the HETGS for 22 ks in
order to 1) search for discrete emission and absorption features, 2)
characterize the neutral absorption edges and 3) test for flux and
spectral feature variation at the 2.01 hr orbital period.


Sequence Number: 500603

Title : Chandra Observation of the Type IIn Supernova 2005bx
PI: Filippenko
Abstract: We propose to observe the recently discovered Type IIn (narrow
emission line) SN 2005bx. Its optical spectrum (ATEL #475) shows it is
similar to the extremely X-ray luminous SN 1988Z, which was observed
at Lx=1e41 erg/s at an age of 6.5 yr. It is unknown what the
early-time (first few weeks to months) Lx of such a SN would be. A
simple constant-density model of the circumstellar (CS) material
around 1988Z predicts an Lx of 1e43 erg/s at an age of a few months
with a hard spectrum. However, the CS interaction is complicated, and
this naive model may not hold (e.g., there could be absorption by the
CS gas). It is difficult to make clear predictions because of the lack
of knowledge. A 30 ks obs of 2005bx (at 130 Mpc) will reach a
sensitivity of ~1e39 erg/s (4 counts). This early observation would be
unique for this interesting and poorly understood class of SNe.
Chandra may only see 2-3 SNe like this during its lifetime, and this
opportunity should not be missed.


Sequence Number: 701180

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started
an all sky survey with INTEGRAL. So far half of the sky at |b|>5d has
been scanned and about 70 sources have been detected above 1 mCrab
limit. 80% of them are known bright AGN. 8 objects are unidentified
and absent from the Rosat All-Sky Survey and AGN catalogs. They are
likely obscured AGN. Short Chandra exposure of their 6' error boxes
will provide unambiguous identification and absorption columns. This
will enable immediate optical follow up and assessment of chosen
survey strategy. Being among brightest extragalactic objects, the
targets are good for future detailed study with Chandra and other
observatories.


Sequence Number: 701179

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started
an all sky survey with INTEGRAL. So far half of the sky at |b|>5d has
been scanned and about 70 sources have been detected above 1 mCrab
limit. 80% of them are known bright AGN. 8 objects are unidentified
and absent from the Rosat All-Sky Survey and AGN catalogs. They are
likely obscured AGN. Short Chandra exposure of their 6' error boxes
will provide unambiguous identification and absorption columns. This
will enable immediate optical follow up and assessment of chosen
survey strategy. Being among brightest extragalactic objects, the
targets are good for future detailed study with Chandra and other
observatories.


Sequence Number: 701178

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started
an all sky survey with INTEGRAL. So far half of the sky at |b|>5d has
been scanned and about 70 sources have been detected above 1 mCrab
limit. 80% of them are known bright AGN. 8 objects are unidentified
and absent from the Rosat All-Sky Survey and AGN catalogs. They are
likely obscured AGN. Short Chandra exposure of their 6' error boxes
will provide unambiguous identification and absorption columns. This
will enable immediate optical follow up and assessment of chosen
survey strategy. Being among brightest extragalactic objects, the
targets are good for future detailed study with Chandra and other
observatories.


Sequence Number: 701177

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started
an all sky survey with INTEGRAL. So far half of the sky at |b|>5d has
been scanned and about 70 sources have been detected above 1 mCrab
limit. 80% of them are known bright AGN. 8 objects are unidentified
and absent from the Rosat All-Sky Survey and AGN catalogs. They are
likely obscured AGN. Short Chandra exposure of their 6' error boxes
will provide unambiguous identification and absorption columns. This
will enable immediate optical follow up and assessment of chosen
survey strategy. Being among brightest extragalactic objects, the
targets are good for future detailed study with Chandra and other
observatories.


Sequence Number: 701176

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started
an all sky survey with INTEGRAL. So far half of the sky at |b|>5d has
been scanned and about 70 sources have been detected above 1 mCrab
limit. 80% of them are known bright AGN. 8 objects are unidentified
and absent from the Rosat All-Sky Survey and AGN catalogs. They are
likely obscured AGN. Short Chandra exposure of their 6' error boxes
will provide unambiguous identification and absorption columns. This
will enable immediate optical follow up and assessment of chosen
survey strategy. Being among brightest extragalactic objects, the
targets are good for future detailed study with Chandra and other
observatories.


Sequence Number: 701175

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started
an all sky survey with INTEGRAL. So far half of the sky at |b|>5d has
been scanned and about 70 sources have been detected above 1 mCrab
limit. 80% of them are known bright AGN. 8 objects are unidentified
and absent from the Rosat All-Sky Survey and AGN catalogs. They are
likely obscured AGN. Short Chandra exposure of their 6' error boxes
will provide unambiguous identification and absorption columns. This
will enable immediate optical follow up and assessment of chosen
survey strategy. Being among brightest extragalactic objects, the
targets are good for future detailed study with Chandra and other
observatories.


Sequence Number: 701174

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started
an all sky survey with INTEGRAL. So far half of the sky at |b|>5d has
been scanned and about 70 sources have been detected above 1 mCrab
limit. 80% of them are known bright AGN. 8 objects are unidentified
and absent from the Rosat All-Sky Survey and AGN catalogs. They are
likely obscured AGN. Short Chandra exposure of their 6' error boxes
will provide unambiguous identification and absorption columns. This
will enable immediate optical follow up and assessment of chosen
survey strategy. Being among brightest extragalactic objects, the
targets are good for future detailed study with Chandra and other
observatories.


Sequence Number: 701173

Title : Search for strongly obscured AGNs: support for INTEGRAL all-sky hard
X-ray survey
PI: Sunyaev
Abstract: While deep observations of small fields are crucial to study weak
distant AGN, all sky shallow surveys are essential for identification
of brightest and/or nearby objects. This is possible with INTEGRAL,
with large FOV and sensitivity peak above 20 keV where dust obscured
and dust free objects are detected equally well. We recently started
an all sky survey with INTEGRAL. So far half of the sky at |b|>5d has
been scanned and about 70 sources have been detected above 1 mCrab
limit. 80% of them are known bright AGN. 8 objects are unidentified
and absent from the Rosat All-Sky Survey and AGN catalogs. They are
likely obscured AGN. Short Chandra exposure of their 6' error boxes
will provide unambiguous identification and absorption columns. This
will enable immediate optical follow up and assessment of chosen
survey strategy. Being among brightest extragalactic objects, the
targets are good for future detailed study with Chandra and other
observatories.


Sequence Number: 500601

Title : GRB050412: The Darkest of the Dark Bursts
PI: Berger
Abstract: Swift localized GRB050412 to few-arcminute precision in real-time
while it was in the night sky over most of the world's major
observatories. While subsequent Swift observations have established
the presence of a fading X-ray afterglow of relatively ordinary flux
(GCN 3253), prompt follow-up observations from UV (GCN 3249) to
optical (GCNs 3238, 3239, 3242) to JHK (GCN 3235) - reaching to
increasingly deep limits from 7.1 sec to 1 hour after the burst - have
established only upper limits to the afterglow flux in these
bandpasses. As with previous events, this is likely due to some
combination of host galaxy extinction and high redshift; since
GRB050412 is the darkest known burst, unusually high redshift and/or
high extinction is indicated. However, the five-arcsec Swift XRT
position will not allow unique identification of a host galaxy. We
therefore propose to make a single Chandra observation to derive a
sub-arcsec position for GRB050412 from its X-ray afterglow.


Sequence Number: 400468

Title : Periastron Observations of a Massive Eclipsing Pulsar Binary System
PI: McLaughlin
Abstract: The 764-ms pulsar J1638-4725 is in an eccentric (e ~ 0.94) orbit with
a 5.3-yr period about a ~ 20 solar mass optically-identified
companion. The pulsar is undetectable in the radio for ~ 1 yr around
periastron, most likely due to absorption and scattering by the dense
stellar environment. During this radio-quiet phase, X-rays from the
"propeller regime" accretion of matter onto the NS magnetosphere are
likely to be detectable. If such emission is detected near periastron
(April 30 2005), this binary will be the first system in which an
accretion phase alternates with a radio pulsar phase, providing a link
between the populations of X-ray transients and radio pulsars and an
important diagnostic of the companion star mass loss rate and its
terminal velocity (and hence mass and radius). X-rays may also be
detected from the pulsar, the companion star, and pulsar wind/disk
shock but are expected to be an order of magnitude less than that
expected from propeller accretion.


Sequence Number: 500600

Title : X-ray observation of a unique radio transient near the Galactic
Center
PI: Hyman
Abstract: We have detected a new unresolved radio transient using the VLA at 330
MHz (Hyman et al. Nature, submitted) which exhibited 10 min flares to
1 Jy at regular 1.25 hr intervals during a 7-hr observation starting
on 2002-09-30. If the source is near the Galactic Center the implied
brightness temperature is several orders of magnitude too high to be
incoherent synchrotron, implying that this is a new class of coherent
emitter. No X-ray emission was seen above 15 mcrab using RXTE bulge
scanning data from the previous and following day, but the field has
never been observed by Chandra or XMM. We propose a 10 ks observation
to search for flaring or quiescent X-ray emission from this source. If
a detection is made this will (1) improve the position of the source
from 10" to <1", (2) constrain source models based on the X-ray flux
and spectrum, and (3) constrain the distance using n_H. If the source
is undetected we will still improve constraints on L_x/L_r by several
orders of magnitude.


Sequence Number: 400467

Title : The nature of the gamma-ray source HESS J1826-148
PI: Funk
Abstract: We (the HESS collaboration) used the first year of operation of the
HESS TeV array to conduct a survey of the inner galaxy. More than a
dozen new and unidentified sources have been discovered (Aharonian et
al., Science, in press). Only one of them, HESS J1826-148, is not
extended and was found to be variable, and should be associated with a
compact object. The TeV source is close to microquasar LS5039, but the
nominal separation of 50" is compatible with a spatial association on
a 9% basis only. Simultaneous XTE-ASM measurements during TeV
observations were uncorrelated. It is plausible that HESS J1826-148 is
actually not coincident with LS5039, but with another compact,
possibly long-lived transient source, which would in any case be the
first example of a new class of TeV emitting sources. We propose DDT
for 8 epochs of simultaneous Chandra & HESS observations to search for
a spatially coincident, hard X-ray source with correlated variability
patterns to enable unambiguous ident.


Sequence Number: 500599

Title : Resolving an X-ray Jet from the Magnetar SGR 1806-20
PI: Kouveliotou
Abstract: On 27 Dec 2004, SGR 1806-20 emitted a giant flare, a once in a century
event with an X-ray peak flux of at least 0.8 erg/cm^2 s. Seven days
later we identified with VLA a bright (172 mJy, 1.4 GHz) expanding
radio source at the location of the SGR, ~500 times brighter than the
radio afterglow seen from SGR 1900+14 following the 1998 August 27
flare. We obtained data with MERLIN separated by 3 days, which show
that within 13 days of the flare a radio structure of angular extent
~100 mas has formed with the peak of the flux displaced ~100 mas
between the two epochs. This elongation immediately suggests a jet
inclined to the line of sight and significantly relativistic, in
analogy with X-ray emission from X-ray binary jets, which have
reheated themselves presumably by the transfer of bulk kinetic energy
to electrons. Discovery of an X-ray jet in a magnetar will provide
unique evidence for the energetics of the shock, the ambient medium
and the B-field of the pulsar.


Sequence Number: 701172

Title : An accretion eruption in the western nucleus of Arp 299
PI: Nandra
Abstract: Monitoring of starburst galaxies in the NIR at WHT in a search for
supernovae (PI: Meikle), has revealed an extraordinary outburst from
NGC 3690, part of merging, LIG system Arp 299 (IAUC 8477). Subtraction
of a Ks image taken on 2005 Jan 30 from earlier images (most recently
2004 June 5) shows a highly variable source within 0.5 of the iron K_
emitter identified by Chandra as the AGN in NGC 3690 (Ballo et al.
ApJ, 600, 634). Such large NIR variability (30%) is generally
restricted to powerful radio-loud QSOs+blazars. What makes this event
even more remarkable is that the AGN in NGC 3690 is usually very weak.
The intrinsic flare is thus likely to be much larger, as the quiescent
NIR emission, which is resolved, is likely dominated by stars. We
propose a Chandra snapshot to confirm the flare and determine its
amplitude. It may be due to a huge accretion event or the rapid
formation of a relativistic jet, heralding NGC 3690 s transition into
a fully-fledged AGN following the merger.


Sequence Number: 500598

Title : The X-ray Fluence of the SGR 1806-20 Hyperflare
PI: Fox
Abstract: On 17 Dec 2004, SGR 1806-20 emitted the brightest burst ever observed
from a Galactic source. This burst, first reported by the Integral
mission (GCN 2920), saturated detectors on every high-energy
satellite. The current lower limit to its fluence, 0.3 erg cm-2 (GCN
2936), would make the burst luminosity roughly 10^46 erg, dozens to
hundreds of times brighter than the "giant flares" that have
previously been observed from other SGRs -- bright enough that
hyperflares in nearby galaxies could contribute to the population of
short-hard gamma-ray bursts (GCN 2942). We propose to make the first
accurate measurement of the fluence in this flare by observing the
X-ray scattering halos produced by molecular clouds between Earth and
SGR 1806-20; five clouds with A_V>2 mag are known from radio
observations (Corbel & Eikenberry 2004, A&A 419, 191). The X-ray rings
from four of these clouds will be observable with Chandra, allowing
four independent estimates of the fluence of the hyperflare.


Sequence Number: 500597

Title : Searching for atomic and/or cyclotron features in the Giant Flares
decay of SGR 1806-20
PI: Rea
Abstract: On 2004 December 27th a Giant Flare from SRG1806-20(GCN 2920) was
revealed, the 1st ever for this source and the 3rd one from SGRs since
1979.The current event is largely more energetic than the previous
ones a rare opportunity to study its decay with the unprecedented
spectral resolution of Chandra,allowing,among other thing to study the
enviroment of the source through the possible presence of spectral
edges/line(similarly to the study performed on GRBs X-ray
afterglows).The comparison of the source emission properties before
and after the flare (XMM obs.carried out few weeks before the
event)will provide an unprecedented opportunity to constrain the
magnetar model and the neutron stars crustal properties.The
possibility of detecting cyclotron features after the flare will
especially be important; in particular,for this source there was
evidence for a cyclotron feature around 5 keV,revealed by RXTE during
a bursting phase.The HETG has the best available resolution around
that energy.


Sequence Number: 200363

Title : Monitoring the X-ray Emission of the Newly Erupted EXor-type V1118
Ori
PI: Audard
Abstract: The origin of the X-ray emission in young, accreting stars remains a
mystery. Accretion seems the dominant mechanism in TW Hya (cool
plasma; high densities). However, other moderately accreting classical
T Tauri stars show high temperatures and low densities. Eruptive young
stars (FUors and EXors) are the key to understanding the importance of
accretion for X-rays since they suddenly display increased accretion
rates from 1E-7 to 1E-4 Msol/year. FUors display brighter and longer
outbursts than EXors but they are far less frequent. Recently, the
(FUor-type) V1647 Ori erupted and triggered an international
observation campaign. In X-rays, Kastner et al. (2004) reported a
30-fold flux increase from the pre-outburst flux, indicating that the
high-energy emission in young stars can increase dramatically due to
the rapid increase of accretion rates in FUor/EXor outbursts. However,
the flux rapidly dropped in the steady high state.


Sequence Number: 400447

Title : Following the decay of the new accretion powered msec pulsar IGR
J00291+5934
PI: Jonker
Abstract: The proposed DDT observations have three goals: 1) As this transient
decays, its magnetic field should become dynamically important. We
will compare the shape of the lightcurve and the spectral information
with that of a NS SXT for which no pulsations have been found. The
strength of the magnetic field is an important unknown quantity for
evolutionary link between LMXBs and msec radio pulsars. 2) A
comparison of the evolution of the SED of this NS SXT with similar
data on black hole (BH) SXTs will constrain the differences in jet
power between NSs and BHs. 3) A comparison of the spectrum and the
luminosity of the source in quiescence immediately after the outburst
with that during an observation in AO7 would allow us to assess the
neutron star cooling after an outburst. Those findings can be compared
with those of the transients XTE J1709-267 and MXB 1658-29 (Jonker et
al. 2003/4; Wijnands et al. 2004).


Sequence Number: 400446

Title : Following the decay of the new accretion powered msec pulsar IGR
J00291+5934
PI: Jonker
Abstract: The proposed DDT observations have three goals: 1) As this transient
decays, its magnetic field should become dynamically important. We
will compare the shape of the lightcurve and the spectral information
with that of a NS SXT for which no pulsations have been found. The
strength of the magnetic field is an important unknown quantity for
evolutionary link between LMXBs and msec radio pulsars. 2) A
comparison of the evolution of the SED of this NS SXT with similar
data on black hole (BH) SXTs will constrain the differences in jet
power between NSs and BHs. 3) A comparison of the spectrum and the
luminosity of the source in quiescence immediately after the outburst
with that during an observation in AO7 would allow us to assess the
neutron star cooling after an outburst. Those findings can be compared
with those of the transients XTE J1709-267 and MXB 1658-29 (Jonker et
al. 2003/4; Wijnands et al. 2004).


Sequence Number: 400445

Title : Following the decay of the new accretion powered msec pulsar IGR
J00291+5934
PI: Jonker
Abstract: The proposed DDT observations have three goals: 1) As this transient
decays, its magnetic field should become dynamically important. We
will compare the shape of the lightcurve and the spectral information
with that of a NS SXT for which no pulsations have been found. The
strength of the magnetic field is an important unknown quantity for
evolutionary link between LMXBs and msec radio pulsars. 2) A
comparison of the evolution of the SED of this NS SXT with similar
data on black hole (BH) SXTs will constrain the differences in jet
power between NSs and BHs. 3) A comparison of the spectrum and the
luminosity of the source in quiescence immediately after the outburst
with that during an observation in AO7 would allow us to assess the
neutron star cooling after an outburst. Those findings can be compared
with those of the transients XTE J1709-267 and MXB 1658-29 (Jonker et
al. 2003/4; Wijnands et al. 2004).


Sequence Number: 800557

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 500591

Title : GRB040912: An Unusual Event Exhibiting Strong Spectral Evolution from
a GRB to an XRF
PI: Ricker
Abstract: The WXM on HETE has localized a GRB event that exhibits highly unusual
spectral evolution. Initially, the emission is hard for 10-20 seconds,
evolving to an XRF over the next 200 seconds. No other event like this
has been detected in the 4 years of HETE operations. The spectral
signature is possibly indicative of a very high redshift event. An
prompt, accurate localization of the X-ray afterglow, the spectrum,
and its decay index by Chandra is requested.


Sequence Number: 500590

Title : GRB040912: An Unusual Event Exhibiting Strong Spectral Evolution from
a GRB to an XRF
PI: Ricker
Abstract: The WXM on HETE has localized a GRB event that exhibits highly unusual
spectral evolution. Initially, the emission is hard for 10-20 seconds,
evolving to an XRF over the next 200 seconds. No other event like this
has been detected in the 4 years of HETE operations. The spectral
signature is possibly indicative of a very high redshift event. An
prompt, accurate localization of the X-ray afterglow, the spectrum,
and its decay index by Chandra is requested.


Sequence Number: 800560

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800559

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800558

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800557

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800556

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800555

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800554

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800553

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800552

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800551

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800550

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 800549

Title : Probing dark energy using the X-ray gas mass fraction in dynamically
relaxed galaxy clusters
PI: Allen
Abstract: We propose to observe a sample of the most X-ray luminous, dynamically
relaxed galaxy clusters identified from the ROSAT All-Sky Survey and
follow-up Chandra snapshot observations. Our primary goals are to
obtain improved constraints on dark energy and the dark equation of
state parameter using the apparent variation of the X-ray gas mass
fraction with redshift. This project represents an opportunity for
Chandra to take the lead in dark energy work. The observations should
lead to a detection of the effects of dark energy from the Chandra
data alone at the ~5sigma level, using only weak priors on the Hubble
constant and mean baryon density of the Universe. When combined with
CMB and supernova data, the observations should constrain the time
averaged dark energy equation of state parameter, w, to better than 10
per cent accuracy (68 per cent confidence limits). The new data will
also be used for joint X-ray/SZ/lensing studies.


Sequence Number: 500585

Title : Search for the Counterpart of a New TeV Gamma-ray Source in the
Galactic Plane
PI: Halpern
Abstract: We propose to examine the error box of the second unidentified TeV
gamma-ray source. The IACT array H.E.S.S. has discovered a source in
the 0.6-10 TeV range, designated VHE J1303-63. It is 0.65 deg north of
the famous Be/X-ray pulsar PSR B1259-63, which was also detected. But
the new source is even brighter than the pulsar, about 0.1 Crab, and
its statistical significance is at least 13 sigma (Beilicke, et al.
2004 Heidelberg Gamma-Ray Meeting, and Beilicke, Aharonian,
Heinzelmann, Hofmann, Wagner, private comm.) The error box of VHE
J1303-63 was covered only by a ROSAT observation, which does not show
any counterpart within the error circle. Since this source is in the
Galactic plane (as is the first unidentified TeV source J2032+4130),
it is likely that its X-ray counterpart is highly absorbed. In a
Chandra DDT observation of TeV J2032+4130, we found a possible hard
X-ray counterpart (Mukherjee et al. 2003, ApJ, 589, 487). We propose a
similar search for VHE J1303-63.


Sequence Number: 500508

Title : Observations of an extremely X-ray rich GRB detected by Integral
PI: Kouveliotou
Abstract: Integral has observed an extremely X-ray rich GRB, the richest seen in
3-40 keV. The event was detected with IBIS; it was also the first ever
seen in the Jem-X FOV. The IBIS spectrum is very soft, with a spectral
index of 2.5 and a flux of 1.4e-8 erg/cm^2 s (15-40 keV). It becomes
very faint after 40 keV and is not detectable above 100 keV. The Jem-X
peak flux (3-20 keV) is 0.5 Crab (~1.4 e-8 erg/cm^2 s); most of this
flux comes below 10 keV! This event is thus a prime example of an XRR
GRB, which may be either a classical GRB seen off axis, or a yet
different class considered to be intrinsically subenergetic GRBs.
There are 3 such bursts observed to date, all associated with SNe. We
have approved ESO observations; these, along with information of the
source position, energetics, and spectrum, as early as possible, would
be crucial in understanding the nature of XRR GRBs and may open a new
window in the field, by probing their early properties with the superb
CXO capabilities.


Sequence Number: 500507

Title : Observations of an extremely X-ray rich GRB detected by Integral
PI: Kouveliotou
Abstract: Integral has observed an extremely X-ray rich GRB, the richest seen in
3-40 keV. The event was detected with IBIS; it was also the first ever
seen in the Jem-X FOV. The IBIS spectrum is very soft, with a spectral
index of 2.5 and a flux of 1.4e-8 erg/cm^2 s (15-40 keV). It becomes
very faint after 40 keV and is not detectable above 100 keV. The Jem-X
peak flux (3-20 keV) is 0.5 Crab (~1.4 e-8 erg/cm^2 s); most of this
flux comes below 10 keV! This event is thus a prime example of an XRR
GRB, which may be either a classical GRB seen off axis, or a yet
different class considered to be intrinsically subenergetic GRBs.
There are 3 such bursts observed to date, all associated with SNe. We
have approved ESO observations; these, along with information of the
source position, energetics, and spectrum, as early as possible, would
be crucial in understanding the nature of XRR GRBs and may open a new
window in the field, by probing their early properties with the superb
CXO capabilities.


Sequence Number: 600412

Title : Monitoring a New X-ray Transient 2.5 Arcseconds South of Sgr A*
PI: Baganoff
Abstract: Chandra observations on 5-6 July reveal a transient 2.5" south (0.1 pc
at 8 kpc) of Sgr A*, in an extreme habitat already known to contain
two dense star clusters and a 3e6 solar-mass black hole. Its 2-8 keV
spectrum (gamma < 0.25) is harder than most INTEGRAL sources. Its
luminosity is >2e34 erg/s, with a possible 4 h period, so it is an
accreting BH or NS, and may emit much of its flux above 10 keV. Thus,
this source may be responsible for much of the emission detected by
INTEGRAL and HESS (TeV) during recent observations of Sgr A*. Also,
diffuse X-rays only 4 light-months from the source have brightened,
suggesting the presence of a jet. We propose to observe the
progression of this outburst: (1) to tell us whether it is active
during upcoming gamma-ray observations, (2) to determine the mechanism
that feeds the source (disk or wind), and (3) to observe the evolution
of the jet. This is a singular opportunity to study the interplay
between accretion, jets, and gamma-ray emission.


Sequence Number: 100052

Title : Chandra by Chandra
PI: Drake
Abstract: A 75ks Chandra observation of the Moon can dramatically increase our
knowledge of lunar geochemistry and provide strong tests of models of
lunar formation and evolution. By resolving fluorescent lines of O,
Mg, Al, and Si, Chandra can provide the first detailed surface
abundance maps of these elements that dominate the crustal and mantle
mineralogy. The results will: (i) provide direct bulk surface
abundances crucial for lunar formation models; (ii) test our
understanding of the Moon's history and crustal evolution through
detailed comparison of abundance ratios within mare, between
geologically diverse lunar surface features, and in craters and ejecta
blankets of different scale; (iii) firmly establish earth orbit X-ray
observation as a powerful means of investigating solar system rocky
bodies; (iv) help prepare for future (c.2005) SMART-1 in-situ lunar
fluorescence measurements; (v) produce high resolution X-ray lunar
images that will likely have significant public appeal.


Sequence Number: 100052

Title : Chandra by Chandra
PI: Drake
Abstract: A 75ks Chandra observation of the Moon can dramatically increase our
knowledge of lunar geochemistry and provide strong tests of models of
lunar formation and evolution. By resolving fluorescent lines of O,
Mg, Al, and Si, Chandra can provide the first detailed surface
abundance maps of these elements that dominate the crustal and mantle
mineralogy. The results will: (i) provide direct bulk surface
abundances crucial for lunar formation models; (ii) test our
understanding of the Moon's history and crustal evolution through
detailed comparison of abundance ratios within mare, between
geologically diverse lunar surface features, and in craters and ejecta
blankets of different scale; (iii) firmly establish earth orbit X-ray
observation as a powerful means of investigating solar system rocky
bodies; (iv) help prepare for future (c.2005) SMART-1 in-situ lunar
fluorescence measurements; (v) produce high resolution X-ray lunar
images that will likely have significant public appeal.


Sequence Number: 100052

Title : Chandra by Chandra
PI: Drake
Abstract: A 75ks Chandra observation of the Moon can dramatically increase our
knowledge of lunar geochemistry and provide strong tests of models of
lunar formation and evolution. By resolving fluorescent lines of O,
Mg, Al, and Si, Chandra can provide the first detailed surface
abundance maps of these elements that dominate the crustal and mantle
mineralogy. The results will: (i) provide direct bulk surface
abundances crucial for lunar formation models; (ii) test our
understanding of the Moon's history and crustal evolution through
detailed comparison of abundance ratios within mare, between
geologically diverse lunar surface features, and in craters and ejecta
blankets of different scale; (iii) firmly establish earth orbit X-ray
observation as a powerful means of investigating solar system rocky
bodies; (iv) help prepare for future (c.2005) SMART-1 in-situ lunar
fluorescence measurements; (v) produce high resolution X-ray lunar
images that will likely have significant public appeal.


Sequence Number: 100053

Title : Chandra Snapshot Spectral Imaging of Comets C/2001 Q4 (NEAT) and
C/2002 T7 (LINEAR)
PI: Lisse
Abstract: The highly favorable perigee passage of the very bright comets C/2001
Q4 (NEAT) and C/2002 T7 (LINEAR) in late May 2004 provides an
opportunity to study cometary x-ray emission in conjunction with the
new CHIPS spectroscopic mission. In 10 ksec of on-target time for each
comet, ACIS-S will obtain snapshot images of the comets in the heart
of the CHIPS 0.05 0.150 keV spectroscopic monitoring period in
late-May 2004. The combined observations have the potential of
directly detecting for the first time the ultra-soft emission due to
Mg, S, Si, and Fe predicted by McCammon et al. (2002) from soft x-ray
background measurements and by Kharchenko et al. (2000, 2003) from
models of solar wind minor ion charge exchange emission. New work by
Wegmann, Dennerl, and Lisse (2004) allows a determination of the
neutral gas production rate from the spatial scale of the emission,
and an independent determination of the solar wind minor ion flux
density using the x-ray surface brightness.


Sequence Number: 100053

Title : Chandra Snapshot Spectral Imaging of Comets C/2001 Q4 (NEAT) and
C/2002 T7 (LINEAR)
PI: Lisse
Abstract: The highly favorable perigee passage of the very bright comets C/2001
Q4 (NEAT) and C/2002 T7 (LINEAR) in late May 2004 provides an
opportunity to study cometary x-ray emission in conjunction with the
new CHIPS spectroscopic mission. In 10 ksec of on-target time for each
comet, ACIS-S will obtain snapshot images of the comets in the heart
of the CHIPS 0.05 0.150 keV spectroscopic monitoring period in
late-May 2004. The combined observations have the potential of
directly detecting for the first time the ultra-soft emission due to
Mg, S, Si, and Fe predicted by McCammon et al. (2002) from soft x-ray
background measurements and by Kharchenko et al. (2000, 2003) from
models of solar wind minor ion charge exchange emission. New work by
Wegmann, Dennerl, and Lisse (2004) allows a determination of the
neutral gas production rate from the spatial scale of the emission,
and an independent determination of the solar wind minor ion flux
density using the x-ray surface brightness.


Sequence Number: 100052

Title : Chandra by Chandra
PI: Drake
Abstract: A 75ks Chandra observation of the Moon can dramatically increase our
knowledge of lunar geochemistry and provide strong tests of models of
lunar formation and evolution. By resolving fluorescent lines of O,
Mg, Al, and Si, Chandra can provide the first detailed surface
abundance maps of these elements that dominate the crustal and mantle
mineralogy. The results will: (i) provide direct bulk surface
abundances crucial for lunar formation models; (ii) test our
understanding of the Moon's history and crustal evolution through
detailed comparison of abundance ratios within mare, between
geologically diverse lunar surface features, and in craters and ejecta
blankets of different scale; (iii) firmly establish earth orbit X-ray
observation as a powerful means of investigating solar system rocky
bodies; (iv) help prepare for future (c.2005) SMART-1 in-situ lunar
fluorescence measurements; (v) produce high resolution X-ray lunar
images that will likely have significant public appeal.


Sequence Number: 100053

Title : Chandra Snapshot Spectral Imaging of Comets C/2001 Q4 (NEAT) and
C/2002 T7 (LINEAR)
PI: Lisse
Abstract: The highly favorable perigee passage of the very bright comets C/2001
Q4 (NEAT) and C/2002 T7 (LINEAR) in late May 2004 provides an
opportunity to study cometary x-ray emission in conjunction with the
new CHIPS spectroscopic mission. In 10 ksec of on-target time for each
comet, ACIS-S will obtain snapshot images of the comets in the heart
of the CHIPS 0.05 0.150 keV spectroscopic monitoring period in
late-May 2004. The combined observations have the potential of
directly detecting for the first time the ultra-soft emission due to
Mg, S, Si, and Fe predicted by McCammon et al. (2002) from soft x-ray
background measurements and by Kharchenko et al. (2000, 2003) from
models of solar wind minor ion charge exchange emission. New work by
Wegmann, Dennerl, and Lisse (2004) allows a determination of the
neutral gas production rate from the spatial scale of the emission,
and an independent determination of the solar wind minor ion flux
density using the x-ray surface brightness.


Sequence Number: 500506

Title : Is GRB 031203 a GRB-SN seen off axis?
PI: Kouveliotou
Abstract: Recent results indicate that there is a common convergence of several
classes of transient phenomena (GRBs, GRB 980425/SN 1998bw, XRFs, and
the most energetic SNe), to a common luminosity ~10^39-10^40 erg/s
about 3-10 years after the explosive event. A simple theoretical
interpretation favors a continuum of events in which the early
luminosity is sensitive to the angle at which the event is observed.
GRB031203 may well be the first of these `gap' events if its X-ray
luminosity can be attributed to its having been viewed substantially
off-axis. Further, if its reported redshift of z=0.105 is confirmed,
GRB031203 is the closest GRB after GRB980425 and thus, an excellent
candidate for a SN to be found in its lightcurve. Indeed, recent
observations (GCN 2544) indicate that this may be the case. Our
suggested 75 ks observation of GRB031203 will provide a luminosity
limit of ~5.5x10^(40) erg/s, comparable to the luminosity seen in SN
1998bw after a few hundred days.


Sequence Number: 100052

Title : Chandra by Chandra
PI: Drake
Abstract: A 75ks Chandra observation of the Moon can dramatically increase our
knowledge of lunar geochemistry and provide strong tests of models of
lunar formation and evolution. By resolving fluorescent lines of O,
Mg, Al, and Si, Chandra can provide the first detailed surface
abundance maps of these elements that dominate the crustal and mantle
mineralogy. The results will: (i) provide direct bulk surface
abundances crucial for lunar formation models; (ii) test our
understanding of the Moon's history and crustal evolution through
detailed comparison of abundance ratios within mare, between
geologically diverse lunar surface features, and in craters and ejecta
blankets of different scale; (iii) firmly establish earth orbit X-ray
observation as a powerful means of investigating solar system rocky
bodies; (iv) help prepare for future (c.2005) SMART-1 in-situ lunar
fluorescence measurements; (v) produce high resolution X-ray lunar
images that will likely have significant public appeal.


Sequence Number: 100052

Title : Chandra by Chandra
PI: Drake
Abstract: A 75ks Chandra observation of the Moon can dramatically increase our
knowledge of lunar geochemistry and provide strong tests of models of
lunar formation and evolution. By resolving fluorescent lines of O,
Mg, Al, and Si, Chandra can provide the first detailed surface
abundance maps of these elements that dominate the crustal and mantle
mineralogy. The results will: (i) provide direct bulk surface
abundances crucial for lunar formation models; (ii) test our
understanding of the Moon's history and crustal evolution through
detailed comparison of abundance ratios within mare, between
geologically diverse lunar surface features, and in craters and ejecta
blankets of different scale; (iii) firmly establish earth orbit X-ray
observation as a powerful means of investigating solar system rocky
bodies; (iv) help prepare for future (c.2005) SMART-1 in-situ lunar
fluorescence measurements; (v) produce high resolution X-ray lunar
images that will likely have significant public appeal.


Sequence Number: 200298

Title : A Star is Born: X-ray Imaging of the Onset of an FU Ori Outburst
PI: Kastner
Abstract: The highest accretion rates among low-mass stars are associated with
the FU Ori (FUor) phase. This phase is marked by ~100-yr-long
outbursts during which a star brightens by 5-15 magnitudes and its
mass accretion rate likely increases by up to a factor of 10^4. The
'standard model' for the formation of Sunlike stars is that they go
through one or more FUor epochs during their pre-main sequence
evolution, and that this phase(s) is when such stars gain most of
their mass. We propose to observe a newly identified FUor during the
rarely observed rise phase of its outburst. This almost certainly will
be the only chance for CXO to make observations of this evolutionary
phase. These observations will be essential in understanding and
improving models for the formation of all low mass stars, and to
inform the ongoing debate concerning the origin of X-rays from young,
low-mass stars (e.g. Kastner et al 2002, ApJ 567, 434).


Sequence Number: 200297

Title : A Star is Born: X-ray Imaging of the Onset of an FU Ori Outburst
PI: Kastner
Abstract: The highest accretion rates among low-mass stars are associated with
the FU Ori (FUor) phase. This phase is marked by ~100-yr-long
outbursts during which a star brightens by 5-15 magnitudes and its
mass accretion rate likely increases by up to a factor of 10^4. The
'standard model' for the formation of Sunlike stars is that they go
through one or more FUor epochs during their pre-main sequence
evolution, and that this phase(s) is when such stars gain most of
their mass. We propose to observe a newly identified FUor during the
rarely observed rise phase of its outburst. This almost certainly will
be the only chance for CXO to make observations of this evolutionary
phase. These observations will be essential in understanding and
improving models for the formation of all low mass stars, and to
inform the ongoing debate concerning the origin of X-rays from young,
low-mass stars (e.g. Kastner et al 2002, ApJ 567, 434).


Sequence Number: 500505

Title : Prompt Observation of the Type Ib/c Supernova 2001em
PI: Pooley
Abstract: The X-ray emission from core-collapse SNe comes from the interaction
of the ejected matter and the circumstellar material, which is the
progenitor's pre-SN wind. It is thus a unique probe of both the
ejected material and the SN environment. We propose a 30 ksec Chandra
obs. of the type Ib/c SN 2001em (which just turned on in the radio; K.
Weiler, IAUC submitted) to determine the X-ray flux to ~5% (see below
for flux estimate) and temperature to ~10%. This information, combined
with continued VLA obs., will determine the mass-loss rate of the
progenitor, thus providing information about both the explosion
environment and the nature of the progenitor. This is especially
important in the case of SNe Ib/c given the association with some
GRBs. Such information will provide a key piece of the puzzle in
understanding the progenitor systems of SNe Ib/c (and by association,
GRBs) and the aftermath of the SN (and GRB) explosion.


Sequence Number: 500504

Title : Monitoring the spectral evolution of RXJ0720-3125 and determining its
nature.
PI: Vink
Abstract: RXJ0720-3125 is a protypical isolated neutron star with a
blackbody-like spectrum. However, we've recently found with
XMM-Newton's RGS that between 5-2000 and 10-2003 its spectrum has
changed. Until 5-2003 this change was slow, but since then the changes
have been dramatic, and the spectrum is now quite distinct from a BB;
it has increased its emission > 0.5 keV & decreased it < 0.5 keV (de
Vries et al. 2004, astro-ph/0401028). We would like to observe this
source with the LETGS in order to see whether the hardening has
continued, is slowly reversing, or whether it is back to its BB-like
state. Moreover, if the source is still in a hard state we need the
LETGS so check whether the absorption < 0.5 keV is Gaussian, in which
case it might be due to proton-cyclotron absorption. NB the deviations
from a BB may relevant to the whole class of isolated NSs, as all of
them may have similar but less obvious deviations from a BB spectrum.


Sequence Number: 701014

Title : Multiwavelength Reverberation Mapping of NGC 4395, the Least Luminous
Seyfert 1 Galaxy
PI: Moran
Abstract: NGC 4395 is the least luminous Seyfert 1 galaxy known, and one of the
most X-ray variable. Its extremely small BH mass implies
light-crossing timescales 100-1000 times shorter than in luminous AGN.
A multiwavelength reverberation mapping campaign on this object
spanning the UV (HST), optical (KPNO 4m & Lick 3m), and IR (KPNO 2.1m
& IRTF 3m) has been approved for two 8-hr periods in April 2004. We
propose to use this unique opportunity to conduct simultaneous
monitoring (2 x 30ks) with Chandra. A previous Chandra observation
revealed extremely rapid, large-amplitude variability and dramatic
long-term spectral variability. Our program will allow us to compare
for the first time the X-ray variability in an AGN of this luminosity
to the UV/optical/IR continuum and emission-line variability. Apart
from indicating the state of the ionizing source during the
reverberation campaign, the Chandra data can shed new light on the
accretion and emission processes in this enigmatic AGN.


Sequence Number: 701013

Title : Multiwavelength Reverberation Mapping of NGC 4395, the Least Luminous
Seyfert 1 Galaxy
PI: Moran
Abstract: NGC 4395 is the least luminous Seyfert 1 galaxy known, and one of the
most X-ray variable. Its extremely small BH mass implies
light-crossing timescales 100-1000 times shorter than in luminous AGN.
A multiwavelength reverberation mapping campaign on this object
spanning the UV (HST), optical (KPNO 4m & Lick 3m), and IR (KPNO 2.1m
& IRTF 3m) has been approved for two 8-hr periods in April 2004. We
propose to use this unique opportunity to conduct simultaneous
monitoring (2 x 30ks) with Chandra. A previous Chandra observation
revealed extremely rapid, large-amplitude variability and dramatic
long-term spectral variability. Our program will allow us to compare
for the first time the X-ray variability in an AGN of this luminosity
to the UV/optical/IR continuum and emission-line variability. Apart
from indicating the state of the ionizing source during the
reverberation campaign, the Chandra data can shed new light on the
accretion and emission processes in this enigmatic AGN.


Sequence Number: 500503

Title : GRB 031203: A Possible Analogue to GRB980425/SN1998bw
PI: Kulkarni
Abstract: GRB03120, a seemingly typical burst was localized to a 5-arcmin region
by Integral. XMM found a source with initial flux of 3E-13 erg/cm2/s
which faded as t^{-0.4} during t=0.25 to 6 days. Separately, we
detected a slowly fading radio counterpart. The X-ray/radio source is
coincident with a bright, z=0.105 galaxy. Relative to other
afterglows, the fading of the radio/X-ray is unusually slow.
Furthermore, the 1E+43 erg/s X-ray luminosity and the 1E+29 erg/s/Hz
radio luminosity are 10 - 1000 times less than for typical afterglows,
yet comparable to those observed for GRB980425/SN1998bw. Most
curiously, there is no optical afterglow or hint of an underlying
supernova. Keck host spectrum rules out an AGN origin for the X-ray
source. We conclude that GRB 031203 is a new type of cosmic explosion
with some parallels. As argued below, our continued VLA campaign
complemented by the proposed Chandra observations offer us the best
chance to decipher the nature of this mysterious source.


Sequence Number: 300145

Title : Outburst in Mira AB?
PI: Karovska
Abstract: The nearby system Mira AB composed of an aging AGB star (Mira A) and a
WD companion (Mira B) offers a unique laboratory for studying wind
accretion processes, a poorly understood phenomenon in many sources.
Recent Chandra ACIS-S Obs.(70ks on 12/6/03; PI.M.Karovska) resolved
for the first time the components (~0.6") in X-rays, and detected a
new bright soft source (< 0.7 keV) in addition to the harder (1-4 keV)
emission from Mira B. The new source is spatially and spectrally
separated from Mira B and likely associated with Mira A. This is the
first detection of X-rays from an AGB star. This source was not
detected by ROSAT in 1993 or recently by XMM 8/03 (AAS/03,J.Kastner),
and could be a transient phenomenon. Model fitting shows that the soft
X-ray emission is likely several emission lines, rather then a
continuum; with ACIS spectral resolution we cannot resolve or identify
these lines. We propose a 40ks LETG+HRC-S obs. to identify the lines
and determine the emission mechanism.


Sequence Number: 300144

Title : A HRC-S LETG Observation of V4743 Sgr
PI: Starrfield
Abstract: We have observed V4743 Sgr three times with CHANDRA (March, July, and
September 2003) with our last cycle ToO program but are now out of
time. We are requesting an additional observation to follow its
evolution back to minimum. Our first observation found a large
amplitude oscillation with a period of ~1300 s (see Sept 2003 ApJ
Letters). Our Xray observations showed that the oscillations were
multi periodic, and that the principal period is increasing. These
results suggest that we are observing non-radial modes and that the
surface characteristics of the WD are evolving on a few month time
scale. We are analyzing the spectra and find that the white dwarf
temperature at the first grating observation was about 600,000K. We
are seeing the WD cool slightly with time. The light curve and
spectral variations are very exciting and we would like to follow the
evolution as long as there is nuclear burning on the white dwarf.


Sequence Number: 400376

Title : A Search for X-Ray Emission from the Double-Pulsar Binary System
J0737-3039
PI: McLaughlin
Abstract: We have discovered the first double neutron star binary, J0737-3039,
in which both stars are observable radio pulsars. The spin periods of
the recycled pulsar, A, and its companion, B, are 22 ms and 2.7 s. The
stars are separated by only 2.9 light seconds in a 2.4-hr orbit. At a
distance of only 500 pc, this system promises to be the best ever
laboratory for relativistic astrophysics. Observations of B show its
flux to vary greatly, making it only detectable for two brief periods
when it is in front of A. This variation is likely due to the
interaction of A's spin-down luminosity, in the form of a relativistic
wind and Poynting flux, with B's magnetosphere. We also see a brief
(22 sec) eclipse of A as it passes behind B. A detection of
non-thermal X-rays from A will provide, for the first time, a probe of
the magnetosphere and local environment of a neutron star. We may also
detect thermal X-rays from B or X-rays from the shock interactions of
this extremely relativistic system.


Sequence Number: 500500

Title : Understanding the nature of the unidentified EGRET source 3EG
J1631-4033
PI: Foschini
Abstract: The EGRET unidentified sources represent one of the most challenging
enterprises of the modern astrophysics. In the 3rd EGRET catalog there
are 271 sources, 170 of them are still unidentified. The identified
sources are mainly blazars (93) and pulsars (5). Now that the most
probable sources are identified, it remains to understand if there are
other populations of objects able to generate high energy (E>100 MeV)
gamma-rays, or if there are different engines powering known objects,
like - for example - transition objects between FRI radio galaxies and
BL Lac or off-beam gamma-ray pulsars of the Gould belt. Given the
high-energy gamma-ray (EGRET) and the hard-X (ISGRI) spectral and
temporal characteristics, this source could be the first example of
off-beam gamma-ray pulsars of the Gould Belt, predicted by several
authors like I. Grenier, N. Gehrels, A. Harding, et al.


Sequence Number: 500499

Title : SN 2003jd; A GRB-like hypernova
PI: Watson
Abstract: SN 2003jd has been identified as a peculiar Type Ic (Stanek et al. GCN
2431) showing strong similarities with SN 1998bw near maximum. However
the spectrum does not match well with other peculiar type Ic's like SN
1997ef or 2002ap. There is an association between GRBs and hypernovae
(HNe), (1998bw/980425 & 2003dh/030329) and it has been suggested that
HNe are GRBs observed off-axis and that HNe-without-GRBs may have
early X-ray emission identifiable with non-thermal afterglow-like
emission. SN 2003jd is an excellent candidate, the best to date, for a
GRB-like HN without an observed GRB and represents an opportunity to
examine the characteristics of a GRB-less HN where the HN appears to
be very similar to those observed in GRBs. The paucity of X-ray data
on HNe & this HN's similarity to a GRB, prompts us to request an
initial imaging observation with Chandra (with a possible follow-up
observation after 1 month), to determine the X-ray luminosity and the
behaviour of the lightcurve.


Sequence Number: 500498

Title : Unveiling the multiwavelength spectrum of the AXP XTEJ1810-197
PI: Israel
Abstract: XTEJ1810-197 is a newly discovered Anomalous X-ray Pulsar (AXP), first
detected by XTE and INTEGRAL and then observed by Chandra (DDT obs.
carried out on 28 August 2003) and XMM (ToO obs.; see Gotthelf et al.
2003, astro-ph/0309745). XTEJ1810-197 is also the first confirmed
example of a transient AXP. The Chandra data allowed to detect
XTEJ1810-197, about 15' off-axis, resulting in a less accurate
position (radius of about 2.5"; 1sigma). On October 7th we carried out
deep IR obs. with the adaptive optic instrument (NACO) mounted on the
VLT. These data allowed us to sort out four faint (Ks>19.5) IR
counterpart candidates to XTEJ1810-197. The latters are separated each
other of more than 1" (within the Chandra uncertainty region of radius
2.5"). Therefore, the requested Chandra on-axis obs. will allow us to
unambiguously identify the counterpart to XTEJ1810-197 (position with
radius of about 0.6" at 90% c.l.).


Sequence Number: 500415

Title : Locating the Transient AXP XTE J1810-197
PI: Gotthelf
Abstract: The newly discovered 5.5s X-ray pulsar XTE J1810-197 (Markwardt et al,
AUC 8168) is the 2nd example of a transient AXP (TAXP). Unlike the
original TAXP, AX J1845-058 (Gotthelf & Vasisht 1998, NA, 3, 293),
this new source was found prior to its fading away; furthermore, an
archival XTE detection provides a spin-down rate, confirming its AXP
status. TAXPs may be related to a growing class of young, isolated NSs
whose properties are distinct from young rotation-powered pulsars, and
whose basic physics is unknown. Examples are, the central compact
object (CCO) in SNR RCW 103, whose flux is variable over years and
lack pulsations, the Cas A point source, another possible quiescent
AXP, based on its spectrum and central SNR location, and the original
TAXP, AX J1845-058, found to be associated with a SNR. Chandra
provides a unique opportunity to characterize a fading AXP, and to
determine an possibly evolutionary link with the CCOs, thus unifying
these mysterious manifestations of NSs.


Sequence Number: 500413

Title : SN2002ic and its Circumstellar Medium
PI: Hughes
Abstract: Supernova (SN) 2002ic (IAUC 8019) is the first thermonuclear or Type
Ia SN ever to show hydrogen in its spectrum (IAUC 8151). Hamuy et al
(astro-ph/0306270) argue that the H alpha emission of the SN arises
from a dense circumstellar medium (CSM), which itself was the result
of pre-SN mass loss from a massive asymptotic giant branch star that
was the companion to the white dwarf that exploded as the SN. This
result could have wide implications for the origin of SNe Ia and their
cosmological use. This study is based on observations taken between
November and February; our more recent VLT data from July continue to
show strong H alpha emission. Radio emission has not been detected
(IAUC 8157), which can be explained if there is substantial free-free
absorption in the CSM gas. Hard X-ray observations are the most
sensitive probe of the CSM surrounding SN Ia; here we propose X-ray
observations of SN2002ic to detect the shocked CSM and confirm the
high mass loss rate of the progenitor.


Sequence Number: 500412

Title : ToO observations of SGR 1806-20 in an active state
PI: Woods
Abstract: SGRs are a class of high-energy transients that emit brief, intense
bursts of soft gamma-rays. There is now strong evidence in support of
the idea that SGRs (and AXPs) are magnetars. SGR 1900+14, SGR 1627-41
and the AXP 1E 2259+586 have shown that during epochs of intense burst
activity, there are changes in the persistent and pulsed emission
properties of the underlying X-ray source. Quantifying these changes
has shed light on the burst mechanism and the consequences of bursts
in magnetars. Details are given in the AO-4 and AO-5 proposals by
Woods et al. SGR 1806-20 recently entered a new phase of activity. As
yet there have been no detections of changes in the persistent
emission of this source during periods of burst activity. The
transient effects of burst activity seen in SGR 1900+14, SGR 1627-41
and 1E 2259+586 are markedly different. Given the low number of
magnetars, it is important to study these transient effects whenever
possible to better understand their nature.


Sequence Number: 400324

Title : Localization and Spectroscopy of the Millisecond X-Ray Pulsar XTE
J1814-338
PI: Chakrabarty
Abstract: A new msec X-ray pulsar (MSXP) , XTE J1814-338 (P=3.2 ms, Porb=1.9 hr)
was just discovered (Markwardt, IAUC submitted). Its orb params are
very similar to those of pulsar SAX J1808.4-3658, the only XRB known
with a brown dwarf donor. J1808 also the only one of 4 prev known
MSXPs whose orb params and disk geometry led to a bright opt
counterpart in outburst. The new psr appears to be geometrically very
similar (from orbit), and it is now anti-Sun, ideal for optical/IR
obs. We are obtaining Magellan optical/IR obs of field, but cannot
obtain opt spectra until 2 arcmin position improved, since field
crowded. Also, J1808 showed strange IR/radio excess early in 1998
outburst that may have been synchtroton (ApJ, 563, L61); if so, soft
X-ray sync excess also expected, possibly with jets, a first for a
NS/pulsar. J1808 was never observed with CXO in outburst. We request
ACIS/HETG for 10 ks to (1) localize source, (2) look for soft
excess/extension, (3) spectrum, (4) HETG to limit pileup.


Sequence Number: 800375

Title : A Chandra Survey of a uniformly-selected sample of high-redshift
galaxy clusters.
PI: Bautz
Abstract: This request is being submitted after consulation with the CXC
Director to compensate for unusually high background during, and
premature termination by SCS 107 of obsid 3577 (seq 800298.) This is a
routine (non-time-critical) request. The high background and early
termination substantially reduced the signal:noise ratio of this
extended, high-redshift cluster.


Sequence Number: 400323

Title : Determining the Nature of the Peculiar X-ray Transient IGR
J16358-4726
PI: Kouveliotou
Abstract: IGR J16358-4726 was discovered on 03/19 2003. Our March 24 CXO
observation serendipitously detected the transient at the 1.7e-10
erg/cm^2 s flux level (unabsorbed) with a very high absorption column
(NH=3.3e23 cm^-2). The spectrum is a hard power law of index 0.5; we
see a significant Fe line and possibly Ni line. A strong flux
modulation with a period of 5860s is clearly visible in the data. The
frequency of this modulation appears to change within the observation.
The only neutron star systems known with similar spin periods are low
luminosity persistent wind-fed pulsars; if this is a spin period, this
transient is a new kind of object. If this is an orbital period, then
the system could be a compact LMXB. We request follow up CXO
observations to quantify short term changes in the 5860s periodicity
and perform phase resolved spectroscopy.


Sequence Number: 500411

Title : Chandra LETG/ACIS Observation of H2650 (=GRB030328)
PI: Ricker
Abstract: GRB030328 is a very bright, long GRB localized to arcminute accuracy
by the HETE SXC in real time at 1120 UT. An observation commencing in
less than 20 hours may permit the detection of Si and S lines (Butler
et al 2003) at a high level of significance.


Sequence Number: 400322

Title : DETERMINATION OF THE POSITION OF THE MILLISECOND PULSAR XTE J1807-294
PI: MARKWARDT
Abstract: Millisecond pulsars are probably the endpoint of evolution of low mass
X-ray binaries (LMXBs). However, the actual detection of neutron star
spin frequencies in LMXBs has been problematic. To date, four
accreting millisecond pulsars have been found, with the fourth, XTE
J1807-294 having been discovered 25 Feb 2003. Three of the four known
pulsars have orbital periods of 35-43 min, which suggests that there
is a common evolutionary origin. We request Chandra HRC-S observations
in "Imaging Mode" primarily to determine the position. This will
enable observations at other wavelengths. Detection of an optical
counterpart of XTE J1807-294, in outburst or quiescence, can aid in
determining the system size and inclination, but because of the
confused galactic center region, it is important to have a precise a
priori position.


Sequence Number: 500410

Title : GRB030226: TESTING THE DUST DESTRUCTION HYPOTHESIS
PI: Pedersen
Abstract: GRB030226 was discovered by HETE-2 and an optical transient identified
2.6h later. The redshift has now been measured to z=1.99 placing it in
an ideal redshift window for combined X-ray and lyman alpha studies:
It is close enough for X-ray absorption in the vicinity of the burst
to be measurable in the CXO spectrum and far enough that lyman alpha
can be reached from the ground. Combining the two measurements with
optical/NIR observations we can accurately determine the amount of
oxygen and iron (dominating the X-ray absorption), the amount of
neutral hydrogen, and the dust content in the GRB environment. For
this burst, we can thus tell if the low dust content, found in most
burst environments, is due to either a) low metallicity and a
universal dust-to-metals ratio, or b) solar metallicity, but a low
dust-to-metal ratio. In case b) most of the metals are in the gas
phase - indicating significant dust destruction.


Sequence Number: 400321

Title : THE BHC SOFT X-RAY TRANSIENT XTE J1908+094 RETURNING TO QUIESCENCE
PI: Jonker
Abstract: With the Chandra satellite we can study the spectra of SXTs as they
fade into quiescence. This has never been done for a BHC SXT!
According to evolutionary and SXT outburst theories there may exist a
whole class of persistent but faint accreting BHCs at low Mdot; their
accretion disk is cold and hence not prone to the SXT outburst
mechanism. Up to now there is very few information on spectral states
for BHCs for ~2 orders of magnitude in flux (~10^-7-10^-5 Edd.; there
is spectral information of BHCs in quiescence at ~10^-8 of Edd.).
Gallo et al. 2003 have demonstrated the existence of a universal
coupling between observed X-ray and radio flux from hard state BHCs,
of the form L_radio~L_X^0.7, over three orders of magnitude. We
propose to extend this relation down to ~5x10^-7 Edd. assuming d=10
kpc. This would demonstrate that jet production is the standard
behavior and it is only in the limited range in Mdot in which a
standard thin disc is formed that a jet is not produced.


Sequence Number: 400320

Title : THE BHC SOFT X-RAY TRANSIENT XTE J1908+094 RETURNING TO QUIESCENCE
PI: Jonker
Abstract: With the Chandra satellite we can study the spectra of SXTs as they
fade into quiescence. This has never been done for a BHC SXT!
According to evolutionary and SXT outburst theories there may exist a
whole class of persistent but faint accreting BHCs at low Mdot; their
accretion disk is cold and hence not prone to the SXT outburst
mechanism. Up to now there is very few information on spectral states
for BHCs for ~2 orders of magnitude in flux (~10^-7-10^-5 Edd.; there
is spectral information of BHCs in quiescence at ~10^-8 of Edd.).
Gallo et al. 2003 have demonstrated the existence of a universal
coupling between observed X-ray and radio flux from hard state BHCs,
of the form L_radio~L_X^0.7, over three orders of magnitude. We
propose to extend this relation down to ~5x10^-7 Edd. assuming d=10
kpc. This would demonstrate that jet production is the standard
behavior and it is only in the limited range in Mdot in which a
standard thin disc is formed that a jet is not produced.


Sequence Number: 400319

Title : THE BHC SOFT X-RAY TRANSIENT XTE J1908+094 RETURNING TO QUIESCENCE
PI: Jonker
Abstract: With the Chandra satellite we can study the spectra of SXTs as they
fade into quiescence. This has never been done for a BHC SXT!
According to evolutionary and SXT outburst theories there may exist a
whole class of persistent but faint accreting BHCs at low Mdot; their
accretion disk is cold and hence not prone to the SXT outburst
mechanism. Up to now there is very few information on spectral states
for BHCs for ~2 orders of magnitude in flux (~10^-7-10^-5 Edd.; there
is spectral information of BHCs in quiescence at ~10^-8 of Edd.).
Gallo et al. 2003 have demonstrated the existence of a universal
coupling between observed X-ray and radio flux from hard state BHCs,
of the form L_radio~L_X^0.7, over three orders of magnitude. We
propose to extend this relation down to ~5x10^-7 Edd. assuming d=10
kpc. This would demonstrate that jet production is the standard
behavior and it is only in the limited range in Mdot in which a
standard thin disc is formed that a jet is not produced.


Sequence Number: 400318

Title : AN HETGS OBSERVATION OF GX 339-4 IN THE LOW/HARD STATE: ACCRETION
GEOMETRY, RELATIVITY, AND JET FORMATION
PI: Miller
Abstract: [The full SJ is contained in an email to the director.] A sensitive
spectrum of a transient Galactic black hole in the low/hard state can
address at least 3 of the most fundamental issues in X-ray astronomy:
1) major pictures for changes in accretion flow geometry with the mass
accretion rate (m-dot), 2) relativistic effects near black holes, and
3) jet formation. GX 339-4 is an ideal target for this purpose. At
present, grating spectra and even CCD spectra obtained from sources in
this state have collected < 10^4 counts each (in the best cases),
insufficient for strong constraints. Our proposed grating observation
will obtain appx 10^6 counts in the dispersed spectrum. We will use
continuum spectroscopy and the shape of the Fe K-alpha line to
constrain the radial location of the inner disk, and thereby the
nature of the flow geometry and the role of the disk in jet formation
in the low/hard state.


Sequence Number: 500409

Title : EXPLORING THE GRB-SUPERNOVA CONNECTION VIA SN2003L
PI: Kulkarni
Abstract: The type Ibc SN 1998bw provides a link between GRBs and supernovae.
Like GRBs, it had relativistic ejecta (as inferred from the brilliant
radio emission and early non-thermal X-ray emission) but with lower
Lorentz factor. Ordinary SNe do not show bright radio emission at
early times and theoretically appear unable to produce significant
relativistic ejecta. Thus it is generally assumed that SN 1998bw
harbored a central engine. For the past four years, we have been
searching for other such engine-driven SNe and have recently reported
bright emission from the type Ic SN2003L. With a radio luminosity that
is currently 1.9E+28 erg/s/Hz (15% of SN1998bw at peak) and rising,
this event is very similar to SN1998bw. A detection of non-thermal
X-ray emission (synchrotron or inverse-Compton) would confirm the
inference of relativistic ejecta and mark SN 2003L as another link
between GRBs and SNe. A 30 ks observation will allow a rough
determination of the spectrum.


Sequence Number: 100038

Title : A SEARCH FOR SOFT X-RAY AURORAS ON EARTH
PI: Gladstone
Abstract: Chandra HRC-I observations of Jupiter made in Dec. 2000 in support of
the Cassini flyby have revealed the surprising result that jovian
auroral x-ray emissions are concentrated in a small `hot spot' which
pulsates with a ~45-m period. The location of the hot spot near the
magnetic pole implies a particle source region near Jupiter's
magnetopause, and high-latitude reconnection of heavy solar wind ions
is now a viable explanation for these soft x-ray emissions. The
identical process should operate at Earth as well. Hard x-ray
emissions from electron bremsstrahlung are well known in the
terrestrial aurora. Surprisingly, however, there have been no searches
of Earth's aurora for emissions at <2keV. We propose here a simple
slew observation by HRC-I across the auroral region to look for
Earth's soft x-ray aurora. The detection of a Jupiter-like hot spot at
Earth would imply that heavy ion solar wind charge exchange is
important for producing x-rays at planets as well as comets.


Sequence Number: 500408

Title : THE DECAYING X-RAY AFTERGLOW OF GRB021004
PI: Sako
Abstract: Observations of the afterglow of GRB021004 have provided us with a
unique opportunity to study the detailed physical conditions of the
burst environment. The optical light curves are densely sampled since
~9.5 minutes after the burst and consist of multiple bumps and wiggles
on various timescales. The X-ray light curve, however, is sampled only
during an earlier Chandra HETG observation, which lasted ~1 day
starting from ~20.5 hours after the burst. The temporal slope during
this observation was determined to be -1.0 +/- 0.2, and there was no
obvious change in spectral shape throughout the observation. As
stressed by Heyl & Perna (astro-ph/021004), the X-ray light curve is
particularly important for distinguishing between the various possible
emission models. We propose to measure the X-ray flux and the spectral
shape of GRB021004 during its late afterglow phases to address the
long-term behaviour of this spectacular afterglow.


Sequence Number: 500407

Title : PROMPT CHANDRA OBSERVATION OF THE TYPE IIN SN 2002HI
PI: Lewin
Abstract: We propose to observe the Type IIn (narrow emission line) SN 2002hi.
Its optical spectra show it is similar to the extremely X-ray luminous
SN 1988Z (IAUC 8006), which was observed at Lx=1e41 erg/s at an age of
6.5yr. It is unknown what the early-time (first few weeks to months)
Lx of such a SN would be. A simple constant density model of the
circumstellar (cs) material around 88Z predicts an Lx of 1e43 erg/s at
an age of a few months with a hard spectrum. However, the cs
interaction is complicated, and this naive model may not hold (e.g.,
there could be absorption by the cs gas). It is difficult to make
clear predictions because of the lack of knowledge. A 10ks obs of 02hi
(at 260 Mpc) will reach a sensitivity as low as ~1e40 erg/s. This
early obs would be unique for this interesting and poorly understood
class of SNe. Chandra may only see 2-3 SNe like this during its
lifetime, and this opportunity should not be missed. In the future, we
will propose for these SNe under Peer Review.


Sequence Number: 500406

Title : PROMPT CHANDRA OBSERVATION OF THE TYPE II SN 2002HH
PI: Lewin
Abstract: We propose to observe the Type II SN 2002hh. As we have shown, Chandra
data will constrain details of the pre-SN evolution and properties of
the SN ejecta and the circumstellar (cs) matter. In our simulations,
we have assumed 1999em-type and 1998S-type spectra, with appropriate
distance and absorption. If 02hh is like 99em, a 30 ksec obs can
determine the flux to ~25% and the temperature to ~50%, which would
constrain cs interaction models. If 02hh is like 98S, we expect ~0.1
cts/sec. A 30ks obs would give us more counts than the >100ks spent on
98S, and we would ALSO be able to determine elemental abundances to
~25-40%, which is even better than was done for 98S. This will
constrain the progenitor mass as it did for 98S. The ONLY REASON we
wish to not trigger our 200ks A04 TOO is the high extinction to 02hh.
If we could use 30ks (and save 170 for another occasion) WE WOULD, but
that may not be allowed. A 30ks DDT obs is a sensible and effective
way to seize this rare opportunity.


Sequence Number: 500405

Title : SPECTROSCOPIC OBSERVATIONS OF THE BRIGHT AFTERGLOW OF GRB021004
PI: Harrison
Abstract: One of the holy grails of gamma-ray burst research is to detect X-ray
line signatures from an afterglow with high statistical significance.
Of all possible observations, this perhaps offers the best chance of
constraining the GRB mechanism and environment, and could provide the
"smoking gun" signature connecting GRBs to massive stellar deaths. In
order to accomplish this, we know long observations within one day of
the event are necessary.


Sequence Number: 500404

Title : GRATING OBSERVATION OF GRB020813
PI: Ricker
Abstract: The SXC on HETE has just localized a very bright (>10 Crab) GRB to an
accuracy of 1 arcmin. Within minutes of the burst location being
disseminated, an optical transient was discovered in the SXC error
box. HETE is expected to detect only 2-3 such events per year with the
SXC. Since this burst has some X-ray characteristics reminescent of
GRB011121 (Reeves et al 2002), a grating observation with Chandra
could establish definitively whether hydrogen-like emission lines from
non-iron metals are characteristic of bright GRBs, as is predicted by
the "supranova" model (Vietri and Stella 1999).


Sequence Number: 600330

Title : SEARCHING FOR THE X-RAY SIGNATURE TO CURRENT RADIO ACTIVITY IN M31*
PI: Primini
Abstract: M31*, the radio source identified with the super-massive black hole in
M31, has recently brightened significantly, from ~50+/-9 microJy on
July 5 to ~90+/-9 microJy on July 29 (5 GHz, VLA). This is the first
significant evidence for radio variability. We request a 5 ksec ACIS-I
observation to determine how this variability is reflected in x-rays.
The typical luminosity of the x-ray counterpart, in several Chandra
observations, is ~4e36 ergs/sec (0.5-7 keV) but it has occasionally
brightened by a factor of 2-4. However, there are no contemporary
radio observations and thus the x-ray/radio correlation is unknown. A
Chandra observation of unusual activity in the x-ray counterpart NOW
would: 1) strengthen the x-ray identification with M31*, which is now
based only on position; 2) constrain source emission models, some of
which predict anti-correlated radio and x-ray variability.


Sequence Number: 400316

Title : INVESTIGATION OF THE UNIQUE UNIDENTIFIED TEV SOURCE, TEV J2032+4130,
IN CYG OB2
PI: Butt
Abstract: Observation by HEGRA at TeV energies has revealed the first, and only,
unidentified TeV source, TeV J2032+4130 at the 4.6sigma level in Cyg
OB2 association. It is marginally consistent with the location of
unidentified EGRET (GeV) source 3EG J2033+4118 and has luminosity
~0.03 Crab in TeV. The source's 2sigma error location circle is just 6
arcmin in radius, well suited to CHANDRA ACIS-I field of view. Chandra
data on point-like vs. diffuse emission + spectra will constrain
source. In particular, we will resolve whether one of the sources
observed by ROSAT, 2RXP 203218.1+412807, seen in one of our Cyg OB2
datasets could be related to the TeV emission -- we cannot tell if the
ROSAT source is intrinsically diffuse or point-like, nor can we yet
constrain its spectrum. We expect an ACIS-I ct rate of ~0.25 cts/sec
from this source. There is some urgency since the source may show
variability on timescales of months. Please see astro-ph/0207528 and
Benaglia et al., A&A,366,605.


Sequence Number: 400315

Title : V4641 SGR DURING OUTBURST: FAST JETS & VARIABLE CORE
PI: Rupen
Abstract: The black-hole X-ray binary (BHXB) V4641 Sgr was discovered in 1999;
0.5" radio jets were seen within 24h of the X-ray flare. Another
outburst in May has produced ongoing optical/radio/X-ray activity. The
apparent jet velocities (9.5c) are the highest yet known; in a few
months they may easily extend over an arcmin. With the past 2 months
of activity, this is an ideal time to look for such extended emission.
The high quiescent luminosity (10x > BHXBs of similar orbital period)
and the strong, very wide Fe line seen in 1999 both suggest X-rays
from the jets: Doppler boosting may explain the luminosity, & the Fe
line suggests entrained/shocked material. We request ToO data to image
these putative X-ray jets, and to check for variability both in the
jets & in the central source. There is an accepted A04 proposal
(Tomsick); but it is important also to observe during the current
outburst, given the extreme variability and high proper motions. We'd
be happy to share these data with Tomsick.


Sequence Number: 400270

Title : OBSERVATION OF CYG X-1 IN THE HIGH STATE WITH HETG/CHANDRA
PI: Feng
Abstract: The 7 HETG/Chandra observations of Cyg X-1 covered the low(LS),
transition(TS) and high(HS) states that showed variable spectral
features. Recent 3 observations (5ks) in HS showed an evidence for
broad Fe K line which is markedly different from that of LS and TS. It
indicates that the disk line may be distorted significantly by strong
relativistic effects near the black hole in HS.However, poor S/N line
profiles in HS did not allow us to measure the relativistic effects,
the inner accretion disk radius which is generally believed very close
to the last stable orbit and can be used to determine the spin of the
hole, ionization states, inclination, etc. We propose 60 ks CC-mode
HETG/Chandra observation of Cyg X-1, which has settled in rare
HS(HR2<0.7, ASM/RXTE since April 2002) to detect the broad line. It is
important also in understanding the physical process which causes the
state transition. A simultaneous RXTE observation will also be planned
to constrain the continuum above 5 keV.


Sequence Number: 400268

Title : FURTHER IMAGING OF THE JETS OF THE BLACK HOLE XTEJ1550-564
PI: Corbel
Abstract: Following our discovery of a radio jet from the black hole candidate
XTEJ1550-564 (IAUC 7795), we detected X-rays from both the western and
eastern jets. The western jet has a sharp peak along its leading edge
(away from the BHC) and is extended along the trailing edge. The
spectrum is a power law with a photon index near 1.7. The eastern jet
gives the first detection of proper motion in X-rays for a jet from a
black hole and proves that the jets move with relativistic speeds on
large scales as hypothesized for AGN jets. The proposed observation
will allow us to study the dynamics of jet/ISM interactions on time
scales inaccessible for AGN jets by determining the evolution of the
flux, morphology, and spectrum of the jets. We will measure the proper
motion of the western jet to an accuracy of 3 mas/day which will show
whether it is still travelling at relativistic speeds (the average
proper motion up to March was 18 mas/day) or has reached a termination
shock.


Sequence Number: 400267

Title : THE LOW/SOFT STATE IN THE MICROQUASAR 1E1740.7-2942
PI: Heindl
Abstract: Based on RXTE monitoring, the microquasar 1E1740.7-2942 has faded and
softened dramatically, entering a "low/soft" state seen only in its
twin microquasar, GRS1758-258. It is unlikely that this state will
occur again for a decade. The usual black hole "high/soft" state
appears at high luminosity, but this low/soft state appears while the
source is dim/fading. We speculate that this is caused by the shutoff
of accretion to two simultaneous flows: a thin disk and a hot, radial
coronal flow. The transition occurs because the hot flow accretes away
rapidly (free-fall timescale) while the disk is consumed on the
viscous timescale (weeks). GRS1758-258 showed an exponential flux
decay with a timescale of about a month after the transition. We
expect similar behavior in 1E1740.7-2942. Chandra will confirm the
presence of a simple disk spectrum seen now without a corona. If the
corona has been ejected, it may detect jets via extended morphology or
Doppler shifted emission lines.


Sequence Number: 400266

Title : THE LOW/SOFT STATE IN THE MICROQUASAR 1E1740.7-2942
PI: Heindl
Abstract: Based on RXTE monitoring, the microquasar 1E1740.7-2942 has faded and
softened dramatically, entering a "low/soft" state seen only in its
twin microquasar, GRS1758-258. It is unlikely that this state will
occur again for a decade. The usual black hole "high/soft" state
appears at high luminosity, but this low/soft state appears while the
source is dim/fading. We speculate that this is caused by the shutoff
of accretion to two simultaneous flows: a thin disk and a hot, radial
coronal flow. The transition occurs because the hot flow accretes away
rapidly (free-fall timescale) while the disk is consumed on the
viscous timescale (weeks). GRS1758-258 showed an exponential flux
decay with a timescale of about a month after the transition. We
expect similar behavior in 1E1740.7-2942. Chandra will confirm the
presence of a simple disk spectrum seen now without a corona. If the
corona has been ejected, it may detect jets via extended morphology or
Doppler shifted emission lines.


Sequence Number: 400265

Title : SPECTROSCOPY OF THE HIGH-LATITUDE ACCRETING MILLISECOND PULSAR XTE
J0929-314
PI: Chakrabarty
Abstract: The 3rd msec X-ray pulsar, XTE J0929-314 (Pspin=5.4 ms, Porb=43 min)
was just discovered (IAUC 7893). Along with the other two (SAX
J1808.4-3658, Pspin=2.5 ms, Porb=2 hr; XTE J1751-305, Pspin=2.3 ms,
Porb=42 min), this establishes a pattern of msec pulsars being found
in very close binaries. The donors in ultracompact binaries (Porb < 80
min) are H-poor and likely degenerate. As seen in CXO observations of
the ultracompact 4U 1626-67 (Schulz et al. 2001, ApJ), this exotic
composition can be traced through X-ray spectroscopy. The source (like
1626) is high-latitude (14 deg) and low-column (Nh<1e21), making it an
ideal target. (J1751 was at Galactic ctr!) From orbital size, a C-O or
O-Ne-Mg donor is likely. We request LETG/ACIS spectra to search for
emission lines and absorption edges. (ACIS for larger area <50 A.) We
also hope to compare the edges with HST UV Ly-alpha measurement of Nh
(HST DDT prop submitted) to explore local composition (cf. 1626
paper).


Sequence Number: 500298

Title : SN2001IG: DETECTING A MASS LOSS PHASE?
PI: Schlegel
Abstract: The X-ray emission of supernovae is a young field with relatively
little data. X-rays provide information about the circumstellar ejecta
as the outgoing shock runs into matter from previous phases of mass
loss. A reverse shock is created which generates low-energy X-rays (~1
keV) while the outgoing shock generates harder events. The X-rays
probe the circumstellar matter and are expected to provide measures of
abundances in spectral lines. The X-ray light curve (LC) additionally
provides a measure of the matter distribution (Ref for SN: Schlegel
1995, Reports on Prog in Physics, 58, 1375). The radio LC of SN1979C
has been interpreted as revealing waves of mass loss (Weiler et al.
1992, ApJ, 399, 672) from the progenitor. No other SN has shown such
behavior prior to the recent increase in the radio LC of SN2001ig. We
expect the hard and soft X-rays to behave differently, directly
testing shock/reverse shock theory.


Sequence Number: 500297

Title : SN2001IG: DETECTING A MASS LOSS PHASE?
PI: Schlegel
Abstract: The X-ray emission of supernovae is a young field with relatively
little data. X-rays provide information about the circumstellar ejecta
as the outgoing shock runs into matter from previous phases of mass
loss. A reverse shock is created which generates low-energy X-rays (~1
keV) while the outgoing shock generates harder events. The X-rays
probe the circumstellar matter and are expected to provide measures of
abundances in spectral lines. The X-ray light curve (LC) additionally
provides a measure of the matter distribution (Ref for SN: Schlegel
1995, Reports on Prog in Physics, 58, 1375). The radio LC of SN1979C
has been interpreted as revealing waves of mass loss (Weiler et al.
1992, ApJ, 399, 672) from the progenitor. No other SN has shown such
behavior prior to the recent increase in the radio LC of SN2001ig. We
expect the hard and soft X-rays to behave differently, directly
testing shock/reverse shock theory.


Sequence Number: 500296

Title : CHANDRA ARCSECOND LOCALIZATION OF THE X-RAY FLASH XRF020427
PI: Fox
Abstract: The X-ray flashes (XRFs) are identified in BeppoSAX observations as
fast X-ray transients that exhibit the properties of gamma-ray burst
(GRB) prompt X-ray counterparts while lacking detectable gamma-ray
emission (Heise et al. 2001, astro-ph/0111246). The XRFs are
distinguished from Galactic phenomena by their nonthermal spectra,
fast evolution, and near-isotropic sky distribution. However, the
absence of gamma-ray emission means that either (1) the XRFs originate
at very high redshifts, z>5; or (2) the XRFs are a GRB-like phenomenon
with Lorentz factors intermediate to GRBs (L>100) and supernovae
(L~1). Chandra, VLA, and HST observations of XRF011030 established for
the first time that, in at least this case, the XRF was the result of
(2) a highly energetic explosion at a cosmological distance z<3 (GCNs
1136, 1143, 1268). Chandra observations of the XRF020427 will allow us
to identify and study only the second such cosmological X-ray flash.


Sequence Number: 500295

Title : CHANDRA ARCSECOND LOCALIZATION OF THE X-RAY FLASH XRF020427
PI: Fox
Abstract: The X-ray flashes (XRFs) are identified in BeppoSAX observations as
fast X-ray transients that exhibit the properties of gamma-ray burst
(GRB) prompt X-ray counterparts while lacking detectable gamma-ray
emission (Heise et al. 2001, astro-ph/0111246). The XRFs are
distinguished from Galactic phenomena by their nonthermal spectra,
fast evolution, and near-isotropic sky distribution. However, the
absence of gamma-ray emission means that either (1) the XRFs originate
at very high redshifts, z>5; or (2) the XRFs are a GRB-like phenomenon
with Lorentz factors intermediate to GRBs (L>100) and supernovae
(L~1). Chandra, VLA, and HST observations of XRF011030 established for
the first time that, in at least this case, the XRF was the result of
(2) a highly energetic explosion at a cosmological distance z<3 (GCNs
1136, 1143, 1268). Chandra observations of the XRF020427 will allow us
to identify and study only the second such cosmological X-ray flash.


Sequence Number: 400247

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400256

Title : VARIABLE THERMAL EMISSION AND FEATURE FROM AQL X-1 IN QUIESCENCE
PI: Rutledge
Abstract: Aql X-1 went into outburst Feb 15 (ATEL 83) and was below 3 sigma
detection in the 1-day ASM countrate on Mar 25. On Apr 1, it has been
undetected with ASM for 7 days, which indicates it has returned to
quiescence. We request observations to monitor the quiescent spectrum
and intensity over 140 days, for 2 goals: (1) Long-term
time-variability was observed between our 4 AO1 observations of Aql
X-1. The variability may be secular, due to slow atmospheric-related
processes, as opposed to stochastic processes like accretion-power.
(2) Two important phenomena related to accretion were observed during
only one (of the four) observations: short time-scale variability
(32+8-6% rms, 1-10000 sec timescale) and a (time-variable) deficit of
counts in the 0.45-0.6 keV band, where the first absorption feature
due to metals in a NS atmosphere should occur. Multiple observations
with the previous sensitivity can again detect variability and the
deficit of counts in >1 observation.


Sequence Number: 400255

Title : VARIABLE THERMAL EMISSION AND FEATURE FROM AQL X-1 IN QUIESCENCE
PI: Rutledge
Abstract: Aql X-1 went into outburst Feb 15 (ATEL 83) and was below 3 sigma
detection in the 1-day ASM countrate on Mar 25. On Apr 1, it has been
undetected with ASM for 7 days, which indicates it has returned to
quiescence. We request observations to monitor the quiescent spectrum
and intensity over 140 days, for 2 goals: (1) Long-term
time-variability was observed between our 4 AO1 observations of Aql
X-1. The variability may be secular, due to slow atmospheric-related
processes, as opposed to stochastic processes like accretion-power.
(2) Two important phenomena related to accretion were observed during
only one (of the four) observations: short time-scale variability
(32+8-6% rms, 1-10000 sec timescale) and a (time-variable) deficit of
counts in the 0.45-0.6 keV band, where the first absorption feature
due to metals in a NS atmosphere should occur. Multiple observations
with the previous sensitivity can again detect variability and the
deficit of counts in >1 observation.


Sequence Number: 400254

Title : VARIABLE THERMAL EMISSION AND FEATURE FROM AQL X-1 IN QUIESCENCE
PI: Rutledge
Abstract: Aql X-1 went into outburst Feb 15 (ATEL 83) and was below 3 sigma
detection in the 1-day ASM countrate on Mar 25. On Apr 1, it has been
undetected with ASM for 7 days, which indicates it has returned to
quiescence. We request observations to monitor the quiescent spectrum
and intensity over 140 days, for 2 goals: (1) Long-term
time-variability was observed between our 4 AO1 observations of Aql
X-1. The variability may be secular, due to slow atmospheric-related
processes, as opposed to stochastic processes like accretion-power.
(2) Two important phenomena related to accretion were observed during
only one (of the four) observations: short time-scale variability
(32+8-6% rms, 1-10000 sec timescale) and a (time-variable) deficit of
counts in the 0.45-0.6 keV band, where the first absorption feature
due to metals in a NS atmosphere should occur. Multiple observations
with the previous sensitivity can again detect variability and the
deficit of counts in >1 observation.


Sequence Number: 400253

Title : VARIABLE THERMAL EMISSION AND FEATURE FROM AQL X-1 IN QUIESCENCE
PI: Rutledge
Abstract: Aql X-1 went into outburst Feb 15 (ATEL 83) and was below 3 sigma
detection in the 1-day ASM countrate on Mar 25. On Apr 1, it has been
undetected with ASM for 7 days, which indicates it has returned to
quiescence. We request observations to monitor the quiescent spectrum
and intensity over 140 days, for 2 goals: (1) Long-term
time-variability was observed between our 4 AO1 observations of Aql
X-1. The variability may be secular, due to slow atmospheric-related
processes, as opposed to stochastic processes like accretion-power.
(2) Two important phenomena related to accretion were observed during
only one (of the four) observations: short time-scale variability
(32+8-6% rms, 1-10000 sec timescale) and a (time-variable) deficit of
counts in the 0.45-0.6 keV band, where the first absorption feature
due to metals in a NS atmosphere should occur. Multiple observations
with the previous sensitivity can again detect variability and the
deficit of counts in >1 observation.


Sequence Number: 400252

Title : VARIABLE THERMAL EMISSION AND FEATURE FROM AQL X-1 IN QUIESCENCE
PI: Rutledge
Abstract: Aql X-1 went into outburst Feb 15 (ATEL 83) and was below 3 sigma
detection in the 1-day ASM countrate on Mar 25. On Apr 1, it has been
undetected with ASM for 7 days, which indicates it has returned to
quiescence. We request observations to monitor the quiescent spectrum
and intensity over 140 days, for 2 goals: (1) Long-term
time-variability was observed between our 4 AO1 observations of Aql
X-1. The variability may be secular, due to slow atmospheric-related
processes, as opposed to stochastic processes like accretion-power.
(2) Two important phenomena related to accretion were observed during
only one (of the four) observations: short time-scale variability
(32+8-6% rms, 1-10000 sec timescale) and a (time-variable) deficit of
counts in the 0.45-0.6 keV band, where the first absorption feature
due to metals in a NS atmosphere should occur. Multiple observations
with the previous sensitivity can again detect variability and the
deficit of counts in >1 observation.


Sequence Number: 400251

Title : VARIABLE THERMAL EMISSION AND FEATURE FROM AQL X-1 IN QUIESCENCE
PI: Rutledge
Abstract: Aql X-1 went into outburst Feb 15 (ATEL 83) and was below 3 sigma
detection in the 1-day ASM countrate on Mar 25. On Apr 1, it has been
undetected with ASM for 7 days, which indicates it has returned to
quiescence. We request observations to monitor the quiescent spectrum
and intensity over 140 days, for 2 goals: (1) Long-term
time-variability was observed between our 4 AO1 observations of Aql
X-1. The variability may be secular, due to slow atmospheric-related
processes, as opposed to stochastic processes like accretion-power.
(2) Two important phenomena related to accretion were observed during
only one (of the four) observations: short time-scale variability
(32+8-6% rms, 1-10000 sec timescale) and a (time-variable) deficit of
counts in the 0.45-0.6 keV band, where the first absorption feature
due to metals in a NS atmosphere should occur. Multiple observations
with the previous sensitivity can again detect variability and the
deficit of counts in >1 observation.


Sequence Number: 400250

Title : VARIABLE THERMAL EMISSION AND FEATURE FROM AQL X-1 IN QUIESCENCE
PI: Rutledge
Abstract: Aql X-1 went into outburst Feb 15 (ATEL 83) and was below 3 sigma
detection in the 1-day ASM countrate on Mar 25. On Apr 1, it has been
undetected with ASM for 7 days, which indicates it has returned to
quiescence. We request observations to monitor the quiescent spectrum
and intensity over 140 days, for 2 goals: (1) Long-term
time-variability was observed between our 4 AO1 observations of Aql
X-1. The variability may be secular, due to slow atmospheric-related
processes, as opposed to stochastic processes like accretion-power.
(2) Two important phenomena related to accretion were observed during
only one (of the four) observations: short time-scale variability
(32+8-6% rms, 1-10000 sec timescale) and a (time-variable) deficit of
counts in the 0.45-0.6 keV band, where the first absorption feature
due to metals in a NS atmosphere should occur. Multiple observations
with the previous sensitivity can again detect variability and the
deficit of counts in >1 observation.


Sequence Number: 400249

Title : OBSERVATIONS OF THE NEWLY DISCOVERED MILLISECOND ACCRETING PULSAR XTE
J1751-305
PI: MARKWARDT
Abstract: Millisecond pulsars are probably the endpoint of evolution of low mass
X-ray binaries (LMXBs). However, the actual detection of neutron star
spin frequencies in LMXBs has been problematic, with SAX J1808.4-3658
being the only known millisecond accreting pulsar. The newly
discovered source (03 Apr 2002) XTE J1751-305 was detected by RXTE PCA
as a 435 Hz pulsar. Ultimately we hope to measure the orbital period
and determine mass constraints for the primary and secondary stars.
This will lead to constraints on population evolution of LMXBs. A
position determined from the BeppoSAX WFC (by J. in 't Zand) refines
the position to within 1.2 arcmin. Because this region is near the
galactic center, a rapid and accurate X-ray position determination is
important. This will enable prompt follow-up observations in the IR
and radio bands. We request Chandra HRC-S observations in "Imaging
Mode" primarily to determine the position, and also to improve the
timing solution.


Sequence Number: 400248

Title : AN ACCURATE POSITION FOR THE BLACK HOLE CANDIDATE XTE J1908+094
PI: Rupen
Abstract: We request a 1 ksec ACIS-S scan of the new transient J1908+094, to
obtain an accurate position to pin down a possible IR/radio
counterpart, as well as a quick X-ray spectrum. The source was
detected by chance during PCA observations of SGR 1900+014 on 21 Feb
2002; a scan on 18 Mar gave a 2' error box ~24' from the SGR, and
showed it had risen from 26 to 64 mCrab (IAUC 7856). The timing
characteristics (IAUC 7856) and a strong hard tail (IAUC 7861) make
this a strong black hole candidate. The field is quite confused in the
near IR, and although our INT I image (19 Mar) suggests a possible
faint counterpart, our VLA data (21-22 Mar) show no radio source at
that position, though there is another (~1 mJy) source within the RXTE
error box. We need a Chandra position to either confirm the IR or
radio counterpart, or to allow much deeper limits based on more
accurate astrometry. There are other possibilities; the I band image
for instance does not rule out a blue counterpart as in J1655-40.


Sequence Number: 500294

Title : CHANDRA ARCSECOND LOCALIZATION OF THE DARK BURST GRB020321
PI: Fox
Abstract: Roughly 1 in 3 arcminute-scale GRB error boxes fail to yield an
optical transient despite intensive ground-based searches. These "dark
bursts" must be subject to severe optical extinction, either within
their host galaxy or because they are located at z>5. Well-localized
dark bursts thus identify highly obscured star-forming galaxies or
galaxies close to the epoch of reionization - objects of great
interest in either case. We propose to localize the dark burst
GRB020321 with a single 20-ks Chandra observation. Despite rapid
notification and a small error box (GCNs 1284, 1285), prompt
observations have failed to reveal an optical or radio afterglow of
this burst (R<24; GCNs 1289, 1305). Given the 2'-radius localization
we anticipate at most two interloping X-ray sources; comparison with
optical datasets will thus allow a unique identification of the GRB
afterglow. The expected X-ray flux will be extrapolated from BeppoSAX
observations to further cement the source identification.


Sequence Number: 400246

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400239

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400238

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400237

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 300090

Title : CHANDRA HETG SPECTROSCOPY OF GK PER IN OUTBURST
PI: Mauche
Abstract: GK Persei is an extraordinary object: the first nova of the last
century, it contains a magnetic white dwarf, an evolved secondary, and
a large truncated accretion disk. ASCA demonstrated that in outburst
the X-ray spectrum of GK Per contains strong Fe K emission lines and a
strong low-energy (0.5-3 keV) excess. The nature of the low-energy
excess is not known, but it is expected to consist of a mixture of
thermal emission lines from the accretion column and fluorescent
emission lines from the white dwarf surface and accretion disk. We
propose to obtain two Chandra HETG observations of GK Per in outburst
to determine the nature of the low-energy emission, measure the Fe K
emission line strengths, and search for other emission lines, thereby
constraining the accretion geometry and the plasma conditions (range
of temperatures, abundances, and density) of the X-ray--emitting
plasma.


Sequence Number: 300089

Title : CHANDRA HETG SPECTROSCOPY OF GK PER IN OUTBURST
PI: Mauche
Abstract: GK Persei is an extraordinary object: the first nova of the last
century, it contains a magnetic white dwarf, an evolved secondary, and
a large truncated accretion disk. ASCA demonstrated that in outburst
the X-ray spectrum of GK Per contains strong Fe K emission lines and a
strong low-energy (0.5-3 keV) excess. The nature of the low-energy
excess is not known, but it is expected to consist of a mixture of
thermal emission lines from the accretion column and fluorescent
emission lines from the white dwarf surface and accretion disk. We
propose to obtain two Chandra HETG observations of GK Per in outburst
to determine the nature of the low-energy emission, measure the Fe K
emission line strengths, and search for other emission lines, thereby
constraining the accretion geometry and the plasma conditions (range
of temperatures, abundances, and density) of the X-ray--emitting
plasma.


Sequence Number: 100034

Title : SPECTROSCOPIC IMAGING OF CHARGE EXCHANGE X-RAY EMISSION FROM COMET
C/2002 C1
PI: Dennerl
Abstract: Comet C/2002 C1, discovered on February 1, 2002, is predicted to be as
bright as 4 - 5 mag when it will become observable with Chandra from
April 10, 2002. We propose to utilize this opportunity for direct
spectroscopic imaging with ACIS-S. This has never been done for such a
bright comet. Thanks to a favorable observing geometry, we can apply a
novel observing technique: as the comet will slowly move along the
comet-Sun line, an automatic scan of the x-ray emission properties
will be provided along this direction, where the charge exchange model
predicts a characteristic spectral evolution, which could, however,
not be tested so far. While previous Chandra images and spectra of
comets suffer from low photon statistics, we expect to get about 40
times more photons than from C/LINEAR S4. This will allow us to
utilize the full spectral and spatial resolution of Chandra. A
detailed Scientific Justification is provided in the attached
Postscript file.


Sequence Number: 500292

Title : TOO OBSERVATIONS OF SGR 1900+14 IN AN UNUSUAL ACTIVE STATE
PI: Woods
Abstract: Previously, we have found that the counterpart to SGR 1900+14
underwent extraordinary spectral changes during burst active episodes
in 1998 and 2001. It is during these epochs where we have gained the
most insight into the nature of this source. SGR 1900+14 recently
entered a new phase of activity starting on 2/17. Our ToO observation
of the SGR on 2/19 with the RXTE PCA found the flux (2-10 keV) to be a
factor of ~20 higher than expected. The pulsed signal of the SGR is
not seen in the data, nor is the pulsed signal of a nearby Be
transient (XTE J1906+09). There are no other catalogued X-ray
transients in the 1 degree radius FWZM fov of the PCA. The power
spectrum did show an excess level of red noise, similar to that seen
in many BHCs. We conclude that we are observing either (i) the rise of
a new transient or (ii) new behavior from SGR 1900+14 in an active
state. A PCA raster scan has shown that the excess emission is
consistent with the direction of the SGR.


Sequence Number: 400236

Title : IMAGING THE JET/ISM INTERACTIONS AROUND THE BLACK HOLE XTEJ1550-564
PI: Corbel
Abstract: We discovered a new radio source, 22" West of the black hole
XTEJ1550-564 (IAUC 7795; 2002 Jan 19). Subsequent observations show it
has a variable spectrum, is extended toward XTEJ1550 and is located
along the axis of the VLBI jets observed during the Sept 1998 radio
flare. Our Chandra images from Aug-Sept 2000 show an extended X-ray
source also along the VLBI jet axis, but directly opposite the radio
source (23" to the East), and with similar flux during the two Chandra
observations (21 days apart). We found a transient radio source in
archival data at this position in Feb 2001, indicating a lifetime of a
few months. It is likely that both components represent superluminal
plasmons ejected during the Sept 1998 major radio flare and
interacting with the ISM. The proposed Chandra observation will allow
us to study the physics of jet/ISM interactions and the total power of
relativistic jets, with implications for our understanding of
relativistic jets from AGN.


Sequence Number: 100034

Title : SPECTROSCOPIC IMAGING OF CHARGE EXCHANGE X-RAY EMISSION FROM COMET
C/2002 C1
PI: Dennerl
Abstract: Comet C/2002 C1, discovered on February 1, 2002, is predicted to be as
bright as 4 - 5 mag when it will become observable with Chandra from
April 10, 2002. We propose to utilize this opportunity for direct
spectroscopic imaging with ACIS-S. This has never been done for such a
bright comet. Thanks to a favorable observing geometry, we can apply a
novel observing technique: as the comet will slowly move along the
comet-Sun line, an automatic scan of the x-ray emission properties
will be provided along this direction, where the charge exchange model
predicts a characteristic spectral evolution, which could, however,
not be tested so far. While previous Chandra images and spectra of
comets suffer from low photon statistics, we expect to get about 40
times more photons than from C/LINEAR S4. This will allow us to
utilize the full spectral and spatial resolution of Chandra. A
detailed Scientific Justification is provided in the attached
Postscript file.


Sequence Number: 500291

Title : LOCALIZATION OF OPTICALLY-DARK GAMMA-RAY BURSTS BY CHANDRA
PI: Ricker
Abstract: Observation will be a second epoch ACIS-I image of the field of a HETE
X-ray rich GRB (XRF011130). The first epoch ACIS-I 30 ksec observation
took place on 10 December. It has been proposed that X-ray rich GRBs
may be at redshifts Z > ~10. To date, no X-ray rich GRB counterpart
has ever been identified. In the first epoch observation, ~20
candidates were established. Since the Chandra X-ray candidates were
localized to <1 arcsec accuracy by Chandra, followup imaging by HST
and spectroscopy by ~8 meter-class ground-based telescopes can
immediately take place after the second epoch Chandra data is
reduced.


Sequence Number: 500287

Title : CHANDRA IDENTIFICATION OF THE X-RAY COUNTERPART OF GRB020127
PI: Fox
Abstract: Roughly one-third of arcminute-scale gamma-ray burst (GRB) error boxes
fail to yield any optical transient in spite of intensive ground-based
follow-up efforts. These so-called "dark GRBs" are likely extinguished
in the optical by dust and gas in their host galaxy: in the one dark
GRB identified (in the radio) so far, GRB970828, modeling efforts
indicate an extinction of >10 mags in R-band (Djorgovski et al. 2001).
Such large extinctions are characteristic of molecular clouds and
star-forming regions, and thus shed light on the nature of GRB
progenitors. The 8-arcminute-radius error circle of GRB020127 was
reported by the HETE-II team within 4.5 hours of the burst (GCN 1229),
was well-placed for immediate observations, and was observed from at
least two facilities (GCNs 1230, 1234), without identification of a
counterpart. Our best hope for counterpart identification thus lies
with the Chandra observations proposed here.


Sequence Number: 500286

Title : CHANDRA IDENTIFICATION OF THE X-RAY COUNTERPART OF GRB020127
PI: Fox
Abstract: Roughly one-third of arcminute-scale gamma-ray burst (GRB) error boxes
fail to yield any optical transient in spite of intensive ground-based
follow-up efforts. These so-called "dark GRBs" are likely extinguished
in the optical by dust and gas in their host galaxy: in the one dark
GRB identified (in the radio) so far, GRB970828, modeling efforts
indicate an extinction of >10 mags in R-band (Djorgovski et al. 2001).
Such large extinctions are characteristic of molecular clouds and
star-forming regions, and thus shed light on the nature of GRB
progenitors. The 8-arcminute-radius error circle of GRB020127 was
reported by the HETE-II team within 4.5 hours of the burst (GCN 1229),
was well-placed for immediate observations, and was observed from at
least two facilities (GCNs 1230, 1234), without identification of a
counterpart. Our best hope for counterpart identification thus lies
with the Chandra observations proposed here.


Sequence Number: 300087

Title : TOO OBSERVATIONS OF THE RECURRENT NOVA IM NORMAE IN OUTBURST
PI: Starrfield
Abstract: IM Nor is a Recurrent Nova (RN) discovered in outburst on 10 Jan 02.
It rose to V~7.7 on 16 Jan suggesting that it was caught at the
beginning of its outburst. Based on its first outburst in 1920 (near
maximum for ~ 100 days), it is one of only two SLOW RN. While CHANDRA
observed another RN with ACIS-S (CI Aql in 2000), the resulting
spectrum was weak. However, CI Aql was fainter at maximum and the
spectrum was taken after it had returned to quiescence. RN may be
progenitors of SN Ia suggesting that we need to obtain as much
information as we can about their properties. We, therefore, propose a
5 ksec ACIS-S observation to see if it is bright in X-rays followed by
a 25 kse c HRC-S+LETG spectrum to study the ejecta. The ACIS-S
spectrum will show either emission lines from a hot gas (seen in V382
Vul) or a hot continuum from a white dwarf atmosphere (V1494 Aql).
Neither of these resemble the spectrum of a dwarf nova (WZ Sge).


Sequence Number: 700612

Title : CHANDRA MONITORING OF A MICROLENSING EVENT IN MG J0414+0534
PI: Chartas
Abstract: Recent Chandra monitoring of the gravitational lens (GL) system MG
J0414+0534 indicate that images C and B are possibly undergoing
microlensing events. The microlensing event in image B is of
particular interest since it is accompanied by a five-fold increase of
the equivalent width of a reprocessed narrow Fe Ka line in the
spectrum of image B. This sudden increase can be explained with a
caustic crossing that selectively enhances a strip of the reflection
emission region of the accretion disk. The main goal of the proposed
DDT observations is to directly probe the various emission regions of
an accretion disk from scales of a few hundred gravitational radii
down to the event horizon of the black hole. We expect to achieve this
goal by monitoring changes in the line energy, intensity, and profile
of an Fe Ka line in image B as a magnification caustic is traversing
the accretion disk of the distant z = 2.64 radio loud quasar MG
J0414+0534.


Sequence Number: 100032

Title : X-RAY OBSERVATIONS OF THE FIRST COUNTERPART TO A FAST X-RAY TRANSIENT,
XRF010930
PI: Harrison
Abstract: Thanks to BeppoSAX we are now aware of a new type of transient --
X-ray flashes (XRFs, also called Fast X-ray Transients). About one
third of the events seen by the WFC are XRFs. Until today, NOT A
SINGLE member of this class has been localized to arcsecond accuracy.
Only gradually has the community come to appreciate that XRFs have a
rate comparable to GRBs. There are two possibilities: 1. XRFs are
highly redshifted GRBs (e.g. Heise, Lloyd) 2) XRFs are explosive
events producing Lorentz factors intermediate between GRBs and SNe and
thus peak in the X-ray. On 30.25 October 2001 (UT) the BeppoSAX Wide
Field Camera (WFC) detected a XRF, XRF011030, and a Chandra DDF has
found an X-ray source coincident with a radio transient (see below).


Sequence Number: 100031

Title : X-RAY OBSERVATIONS OF THE FIRST COUNTERPART TO A FAST X-RAY TRANSIENT,
XRF010930
PI: Harrison
Abstract: Thanks to BeppoSAX we are now aware of a new type of transient --
X-ray flashes (XRFs, also called Fast X-ray Transients). About one
third of the events seen by the WFC are XRFs. Until today, NOT A
SINGLE member of this class has been localized to arcsecond accuracy.
Only gradually has the community come to appreciate that XRFs have a
rate comparable to GRBs. There are two possibilities: 1. XRFs are
highly redshifted GRBs (e.g. Heise, Lloyd) 2) XRFs are explosive
events producing Lorentz factors intermediate between GRBs and SNe and
thus peak in the X-ray. On 30.25 October 2001 (UT) the BeppoSAX Wide
Field Camera (WFC) detected a XRF, hereafter XRF011030, unaccompanied
by any increased rate in the Gamma Ray Burst Monitor (GRBM) on SAX,
HETE-2 or Ulysses.


Sequence Number: 400234

Title : CYGNUS X-1 IN THE HIGH STATE
PI: Cui
Abstract: Cyg X-1 is now in a rare high state, as seen by the ASM and radio
monitoring. Such a state transition occurs only once every few years,
and therefore offers a great opportunity for us to conduct a detailed
study of this important black hole candidate in the high state, making
use some of the unprecedented capabilities offered by Chandra.
Previous Chandra observations of the source have revealed the presence
of numerous emission lines and absorption edges (Schulz et al. 2001).
There is already evidence that the line emission seems to vary
depending upon the state of the source (low state vs. flare). It
would, therefore, be very interesting to see how the source behaves in
the high state. The results would almost certainly shed light on the
difference in X-ray production processes and the binary environment
between the low and high states, and, ultimately, on the physical
process that is responsible for triggering a state transiton.


Sequence Number: 500285

Title : ARCHIVAL RESEARCH FOR ISOLATED NEUTRON STAR RXJ185635-3754
PI: Tananbaum
Abstract: A long LETG observation will provide a high signal-to-noise
high-resolution spectrum, permitting a search for the signatures of
heavy elements (beyond He) in the neutron star atmosphere. If such
features can be detected and identified, their redshift and profiles
can be used to provide constraints on the neutron star equation of
state.


Sequence Number: 700608

Title : CHANDRA MONITORING OF A MICROLENSING EVENT IN MG J0414+0534
PI: Chartas
Abstract: Recent Chandra monitoring of the gravitational lens (GL) system MG
J0414+0534 indicate that images C and B are possibly undergoing
microlensing events. The microlensing event in image B is of
particular interest since it is accompanied by a five-fold increase of
the equivalent width of a reprocessed narrow Fe Ka line in the
spectrum of image B. This sudden increase can be explained with a
caustic crossing that selectively enhances a strip of the reflection
emission region of the accretion disk. The main goal of the proposed
DDT observations is to directly probe the various emission regions of
an accretion disk from scales of a few hundred gravitational radii
down to the event horizon of the black hole. We expect to achieve this
goal by monitoring changes in the line energy, intensity, and profile
of an Fe Ka line in image B as a magnification caustic is traversing
the accretion disk of the distant z = 2.64 radio loud quasar MG
J0414+0534.


Sequence Number: 500285

Title : ARCHIVAL RESEARCH FOR ISOLATED NEUTRON STAR RXJ185635-3754
PI: Tananbaum
Abstract: A long LETG observation will provide a high signal-to-noise
high-resolution spectrum, permitting a search for the signatures of
heavy elements (beyond He) in the neutron star atmosphere. If such
features can be detected and identified, their redshift and profiles
can be used to provide constraints on the neutron star equation of
state.


Sequence Number: 500285

Title : ARCHIVAL RESEARCH FOR ISOLATED NEUTRON STAR RXJ185635-3754
PI: Tananbaum
Abstract: A long LETG observation will provide a high signal-to-noise
high-resolution spectrum, permitting a search for the signatures of
heavy elements (beyond He) in the neutron star atmosphere. If such
features can be detected and identified, their redshift and profiles
can be used to provide constraints on the neutron star equation of
state.


Sequence Number: 500285

Title : ARCHIVAL RESEARCH FOR ISOLATED NEUTRON STAR RXJ185635-3754
PI: Tananbaum
Abstract: A long LETG observation will provide a high signal-to-noise
high-resolution spectrum, permitting a search for the signatures of
heavy elements (beyond He) in the neutron star atmosphere. If such
features can be detected and identified, their redshift and profiles
can be used to provide constraints on the neutron star equation of
state.


Sequence Number: 400233

Title : LOCALIZATION AND IDENTIFICATION OF THE X-RAY TRANSIENT IN NGC 6440
PI: in 't Zand
Abstract: X1745-203 in NGC 6440 is one of five X-ray transients in galactic
globular clusters, with recorded outbursts in 1971 and 1998. The last
outburst (In 't Zand et al, 1998, A&A 345, 100) was followed up by us
with VLT and NTT observations which identified two candidate optical
counterparts (Verbunt et al, 2000, A&A 359, 960). Both of these have
counterparts in a Chandra observation of NGC 6440 taken during
quiescence in July 2000. An accurate position of the X-ray transient
while it is active would secure the identification of the quiescent
X-ray as well as the optical counterpart. With such an identification,
we can study the quiescent X-ray emission and determine what it is due
to. One of the most likely explanations is emission from a cooling
neutron star; if so, given the known distance, we can directly measure
the neutron-star radius. ASM/RXTE observations show that X1745-203 has
gone into outburst again, and this presents the opportunity to
determine the position of the transient.


Sequence Number: 700607

Title : CHANDRA OBSERVATIONS OF THE THREE HIGHEST REDSHIFT QUASARS FROM THE
SDSS
PI: Brandt
Abstract: X-ray studies of the highest redshift quasars provide insight into the
evolution of quasar central power sources and environments. Large
X-ray efforts (e.g., XEUS and Constellation-X) are being planned to
study the z=5-20 Universe despite a lack of X-ray information on the
Universe at these redshifts. Chandra can efficiently provide precious,
basic information on the highest redshift quasars due to its high
sensitivity. Three high-redshift quasars at z=6.28, 5.99, 5.82 have
been recently discovered by the Sloan Digital Sky Survey; they are
bright with AB_1450=19.7, 19.6, 18.8. We propose exploratory Chandra
observations of these three objects designed to define their basic
X-ray properties and determine if spectroscopic X-ray observations are
merited. If these quasars are detected, this will hopefully capture
the public's interest leading to further appreciation of the power of
Chandra. Co-Is on this proposal are SDSS members Anderson, Fan, Gunn,
Richards, Schneider, Strauss, Voges.


Sequence Number: 700606

Title : CHANDRA OBSERVATIONS OF THE THREE HIGHEST REDSHIFT QUASARS FROM THE
SDSS
PI: Brandt
Abstract: X-ray studies of the highest redshift quasars provide insight into the
evolution of quasar central power sources and environments. Large
X-ray efforts (e.g., XEUS and Constellation-X) are being planned to
study the z=5-20 Universe despite a lack of X-ray information on the
Universe at these redshifts. Chandra can efficiently provide precious,
basic information on the highest redshift quasars due to its high
sensitivity. Three high-redshift quasars at z=6.28, 5.99, 5.82 have
been recently discovered by the Sloan Digital Sky Survey; they are
bright with AB_1450=19.7, 19.6, 18.8. We propose exploratory Chandra
observations of these three objects designed to define their basic
X-ray properties and determine if spectroscopic X-ray observations are
merited. If these quasars are detected, this will hopefully capture
the public's interest leading to further appreciation of the power of
Chandra. Co-Is on this proposal are SDSS members Anderson, Fan, Gunn,
Richards, Schneider, Strauss, Voges.


Sequence Number: 700605

Title : CHANDRA OBSERVATIONS OF THE THREE HIGHEST REDSHIFT QUASARS FROM THE
SDSS
PI: Brandt
Abstract: X-ray studies of the highest redshift quasars provide insight into the
evolution of quasar central power sources and environments. Large
X-ray efforts (e.g., XEUS and Constellation-X) are being planned to
study the z=5-20 Universe despite a lack of X-ray information on the
Universe at these redshifts. Chandra can efficiently provide precious,
basic information on the highest redshift quasars due to its high
sensitivity. Three high-redshift quasars at z=6.28, 5.99, 5.82 have
been recently discovered by the Sloan Digital Sky Survey; they are
bright with AB_1450=19.7, 19.6, 18.8. We propose exploratory Chandra
observations of these three objects designed to define their basic
X-ray properties and determine if spectroscopic X-ray observations are
merited. If these quasars are detected, this will hopefully capture
the public's interest leading to further appreciation of the power of
Chandra. Co-Is on this proposal are SDSS members Anderson, Fan, Gunn,
Richards, Schneider, Strauss, Voges.


Sequence Number: 300067

Title : FIRST X-RAY OBSERVATIONS DURING AN EXTREMELY RARE OUTBURST OF WZ SGE
PI: Kuulkers
Abstract: The cataclysmic variable (CV) WZ Sge has unexpectedly gone into
outburst on 2001 Jul 23 (IAU Circ 7669). Outbursts were seen in 1913,
1946 and 1978 (e.g. ApJ 248, 1067), suggesting a recurrence time of
~33 years. These extremely rare outbursts, and their decline to
quiescence have NEVER been covered in X-rays. With Chandra we have the
unique opportunity to study WZ Sge for the first time through these
phases. In quiescence the accretion disk is truncated by the white
dwarf magnetic field and X-ray oscillations (PASP 110, 403) at 27.9s
were observed. In outburst the disk reaches the white dwarf surface
(e.g. MNRAS 305, 473) and possibly the oscillations cease to exist. By
taking 10 ksec snapshots of WZ Sge 3 times in the next 2-3 months, we
will catch WZ Sge in its various states, and get information on
accretion rate onto the white dwarf, abundances, and temperatures,
etc. (e.g. MNRAS 288, 649). We have requested a DDT on HST as well
(PI: E. Sion).


Sequence Number: 300066

Title : FIRST X-RAY OBSERVATIONS DURING AN EXTREMELY RARE OUTBURST OF WZ SGE
PI: Kuulkers
Abstract: The cataclysmic variable (CV) WZ Sge has unexpectedly gone into
outburst on 2001 Jul 23 (IAU Circ 7669). Outbursts were seen in 1913,
1946 and 1978 (e.g. ApJ 248, 1067), suggesting a recurrence time of
~33 years. These extremely rare outbursts, and their decline to
quiescence have NEVER been covered in X-rays. With Chandra we have the
unique opportunity to study WZ Sge for the first time through these
phases. In quiescence the accretion disk is truncated by the white
dwarf magnetic field and X-ray oscillations (PASP 110, 403) at 27.9s
were observed. In outburst the disk reaches the white dwarf surface
(e.g. MNRAS 305, 473) and possibly the oscillations cease to exist. By
taking 10 ksec snapshots of WZ Sge 3 times in the next 2-3 months, we
will catch WZ Sge in its various states, and get information on
accretion rate onto the white dwarf, abundances, and temperatures,
etc. (e.g. MNRAS 288, 649). We have requested a DDT on HST as well
(PI: E. Sion).


Sequence Number: 300065

Title : FIRST X-RAY OBSERVATIONS DURING AN EXTREMELY RARE OUTBURST OF WZ SGE
PI: Kuulkers
Abstract: The cataclysmic variable (CV) WZ Sge has unexpectedly gone into
outburst on 2001 Jul 23 (IAU Circ 7669). Outbursts were seen in 1913,
1946 and 1978 (e.g. ApJ 248, 1067), suggesting a recurrence time of
~33 years. These extremely rare outbursts, and their decline to
quiescence have NEVER been covered in X-rays. With Chandra we have the
unique opportunity to study WZ Sge for the first time through these
phases. In quiescence the accretion disk is truncated by the white
dwarf magnetic field and X-ray oscillations (PASP 110, 403) at 27.9s
were observed. In outburst the disk reaches the white dwarf surface
(e.g. MNRAS 305, 473) and possibly the oscillations cease to exist. By
taking 10 ksec snapshots of WZ Sge 3 times in the next 2-3 months, we
will catch WZ Sge in its various states, and get information on
accretion rate onto the white dwarf, abundances, and temperatures,
etc. (e.g. MNRAS 288, 649). We have requested a DDT on HST as well
(PI: E. Sion).


Sequence Number: 300061

Title : WZ SGE IN OUTBURST TEN YEARS EARLY: II THE X-RAY EMISSION
PI: Wheatley
Abstract: This is the second half of the WZ Sge DDT proposal. In the first we
requested HRC-S/LETG spectrscopy of the EUV emission. Here we request
ACIS-S observations of the (probably weak) X-ray emission. The X-ray
emission is likely to be supressed below its usual quiescent level
during the outburst, as the emission is thought to switch to the EUV.
However, WZ Sge has never been observed in X-rays during outburst.


Sequence Number: 300059

Title : WZ SGE IN OUTBURST TEN YEARS EARLY: I THE EUV EMISSION
PI: Wheatley
Abstract: WZ Sge is the most extreme dwarf nova. While most dwarf novae exhibit
outbursts every few weeks with optical amplitudes of 2-3 magnitudes,
WZ Sge waits thirty years between outbursts which then have amplitudes
of 7 mag. These have never been studied in X-rays. WZ Sge is in
outburst right now (began around July 23.5 UT) presenting a unique
opportunity to observe it in outburst with Chandra. We are extremely
lucky because the outburst was not expected for another ten years, and
may not repeat for another 30 years. In general dwarf novae are weak
hard X-ray sources in quiescence and strong EUV sources in outburst.
We may expect the same behaviour from WZ Sge though we must also be
prepared for unexpected behaviour from such an extreme system. Count
rates are highly uncertain, but we may expect WZ Sge to be the
brightest EUV source in the sky. We propose LETG spectroscopy to study
the EUV component and ACIS-S spectrscopy of the (probably weaker) hard
emission.


Sequence Number: 300058

Title : WZ SGE IN OUTBURST TEN YEARS EARLY: I THE EUV EMISSION
PI: Wheatley
Abstract: WZ Sge is the most extreme dwarf nova. While most dwarf novae exhibit
outbursts every few weeks with optical amplitudes of 2-3 magnitudes,
WZ Sge waits thirty years between outbursts which then have amplitudes
of 7 mag. These have never been studied in X-rays. WZ Sge is in
outburst right now (began around July 23.5 UT) presenting a unique
opportunity to observe it in outburst with Chandra. We are extremely
lucky because the outburst was not expected for another ten years, and
may not repeat for another 30 years. In general dwarf novae are weak
hard X-ray sources in quiescence and strong EUV sources in outburst.
We may expect the same behaviour from WZ Sge though we must also be
prepared for unexpected behaviour from such an extreme system. Count
rates are highly uncertain, but we may expect WZ Sge to be the
brightest EUV source in the sky. We propose LETG spectroscopy to study
the EUV component and ACIS-S spectrscopy of the (probably weaker) hard
emission.


Sequence Number: 300057

Title : WZ SGE IN OUTBURST TEN YEARS EARLY: I THE EUV EMISSION
PI: Wheatley
Abstract: WZ Sge is the most extreme dwarf nova. While most dwarf novae exhibit
outbursts every few weeks with optical amplitudes of 2-3 magnitudes,
WZ Sge waits thirty years between outbursts which then have amplitudes
of 7 mag. These have never been studied in X-rays. WZ Sge is in
outburst right now (began around July 23.5 UT) presenting a unique
opportunity to observe it in outburst with Chandra. We are extremely
lucky because the outburst was not expected for another ten years, and
may not repeat for another 30 years. In general dwarf novae are weak
hard X-ray sources in quiescence and strong EUV sources in outburst.
We may expect the same behaviour from WZ Sge though we must also be
prepared for unexpected behaviour from such an extreme system. Count
rates are highly uncertain, but we may expect WZ Sge to be the
brightest EUV source in the sky. We propose LETG spectroscopy to study
the EUV component and ACIS-S spectrscopy of the (probably weaker) hard
emission.


Sequence Number: 300056

Title : THE RECURRENT NOVA CI AQL
PI: Greiner
Abstract: We propose a 20 ksec ACIS-S observation of the recurrent nova (RN) CI
Aql. RNe are expected to emit soft x-rays during an interval after the
ejected shell has become optically thin and before the hydrogen
shell-burning ceases and the white dwarf cools. A 2 ksec Chandra
ACIS-S observation on June 1, 2001 discovered that CI Aql was a soft
X-ray source 380 days after outburst. The flux was much smaller than
expected. It is possible that the shell is dense and/or expanding
slowly; i.e. we may still be near the beginning of the soft X-ray
phase. If obscuration is still important, the proposed observation
will detect a distinctive spectral signature and will measure the
ejected mass, testing whether CI Aql is a possible SNIa progenitor. If
obscuration is not important, we will determine the temperature and
luminosity of the white dwarf. Making these measurements and adding a
second point to the X-ray light curve, will significantly add to the
evolving understanding of the properties of RNe.


Sequence Number: 300054

Title : THE RECURRENT NOVA CI AQL
PI: Greiner
Abstract: Recurrent novae (RN) are expected to emit soft x-rays during a short
interval after the ejected shell has become optically thin and before
the hydrogen shell-burning ceases. Observations of the soft x-rays
will test theoretical models and will also test the conjecture that RN
are SN Ia progenitors. Unfortunatley, no RN occurred during the ROSAT
years, and in fact only one has been detected as a soft X-ray emitter
(Kahabka etal 1999). CI Aql went into outburst in Apr. 2000. Hachisu &
Kato (2001; astro-ph/0104461) predict that CI Aql should have recently
become active at soft X-ray wavelengths and is potentially detectable
until Aug. 2001. We propose (1) a 2 ksec ACIS-S observation to verify
the existence of soft X-rays, and (2) if soft X-rays are discovered, a
20 ksec LETG-HRC observation to determine crucial parameters (white
dwarf mass, effective temperature, composition, luminosity, wind
properties).


Sequence Number: 500200

Title : TOO OBSERVATIONS OF SGR 1900+14 IN AN ACTIVE STATE
PI: Kouveliotou
Abstract: SGR 1900+14 has just emitted a second giant flare (GCN #1041); this is
the second source, which has emitted giant flares (01/04/18 and
98/08/27), in the last 20 years. SGR flares are extremenly rare events
and release over 10^44 ergs. The previous flare, changed the pulse
shape of the neutron star significantly (from four peaks to a single
peak sinusoid) indicating dramatic B-field changes. We have evidence
(yet unpublished) that the pulse shape is changing back to its complex
form. We wish to investigate and understand: 1) whether there is
another pulse shape change associated with the current SGR activity,
2) whether there is a persistent flux change and confirm the
persistent flux-flare energy output relation we have seen previously,
and 3) whether we confirm a line around 6 keV seen during a burst
emitted two days after the SGR 1900+14 August 27, 1998 flare. If this
is a proton cyclotron line, we will for the first time be able to
measure directly the magnetic field of a magnetar


Sequence Number: 500199

Title : IMMEDIATE POST-GIANT FLARE OBSERVATIONS OF SGR 1900+14
PI: Kulkarni
Abstract: The Soft Gamma-Ray Repeaters (SGRs) are thought to be magnetars:
isolated neutron stars with dipolar magnetic field strengths in excess
of 1e14 G. The best evidence for this identification are the "giant
flares" of these sources, which are highly super-Eddington and require
the confining pressure and reduced photon cross-section of a strong
B-field. The 27 August 1998 flare of SGR 1900+14 peaked at L_X > 2e43
erg/s and powered a short-lived synchrotron nebula of 8.5 GHz flux >
0.3 mJy at its peak. Chandra ACIS-S observations of SGR 1900+14 in the
near aftermath of its recent flare (GCN 1041) will enable a search for
spectral features in the post-flare X-ray emission, which may exhibit
~1e37 erg/s bursts of its own. Strohmayer & Ibrahim (2000) have
reported a ~6.4 keV line with XTE observations of SGR 1900+14;
detection of this line with ACIS will provide valuable insight into
these objects. Coordinated observations with the VLA/VLBA are
underway, and will be arranged with RXTE.


Sequence Number: 700393

Title : THE ORIGIN OF THE DRAMATIC FLUX AND SPECTRAL VARIABILITY IN THE
CIRCINUS GALAXY
PI: Matt
Abstract: The Circinus Galaxy is one of the nearest AGN and the brightest
Compton-thick Seyfert 2. Due to heavy obscuration, below 10 keV the
spectrum is dominated by a reflection component, the nucleus starting
to be observable above ~20 keV. No evidence for variability was
present before we observed the Circinus Galaxy with BeppoSAX on 2001
January 7. The source has dramatically changed with since June 2000
both in flux and spectral shape. Below 10 keV, the flux increases by
almost 50\%,the spectrum becoming steeper. Above that energy, the
change was much smaller, if any. There are two explanations: a) A past
variation of the nuclear emission echoed by the reflection component.
b) A burst from a off-center source reaching the luminosity of 10**40
erg/s, as that observed in M82 and attributed to accretion onto a
black hole with a few hundred times the solar mass BeppoSAX cannot
solve this ambiguity. Only a high angular resolution observation with
Chandra can do it.


Sequence Number: 400164

Title : HIGH RESOLUTION SPECTROSCOPY OF THE POSSIBLE JETS IN GRS 1758-258
PI: Heindl
Abstract: As of 28 Feb, the microquasar GRS1758-258 has entered an extremely dim
x-ray state (RXTE- IAUC submitted). This is unlikely to happen again
for 10 years. Two HRC observations in 2000 Sept/Oct revealed a
variable point source plus elongated (~1") emission. In one month, the
morphology changed showing the likely formation of an ~arcsecond x-ray
jet. At the likely source distance (8.5kpc), relativistic bulk motion
would be required. The current state is ~3x dimmer in RXTE than
typical. We suspect the point source has turned off, and the residual
flux is from ejected material. Cui et al. (ACIS/HETG,
astro-ph/0009380) found extended emission around another microquasar,
1E1740.7-2942, and may have detected spectral lines, but they could
not separate the core and extended components. We will measure the
spectrum of the extended (jet?) emission without point source
contamination. This has the possibility of discovering red and
blue-shifted emission lines a la SS433.


Sequence Number: 400163

Title : HIGH RESOLUTION SPECTROSCOPY OF THE POSSIBLE JETS IN GRS 1758-258
PI: Heindl
Abstract: As of 28 Feb, the microquasar GRS1758-258 has entered an extremely dim
x-ray state (RXTE- IAUC submitted). This is unlikely to happen again
for 10 years. Two HRC observations in 2000 Sept/Oct revealed a
variable point source plus elongated (~1") emission. In one month, the
morphology changed showing the likely formation of an ~arcsecond x-ray
jet. At the likely source distance (8.5kpc), relativistic bulk motion
would be required. The current state is ~3x dimmer in RXTE than
typical. We suspect the point source has turned off, and the residual
flux is from ejected material. Cui et al. (ACIS/HETG,
astro-ph/0009380) found extended emission around another microquasar,
1E1740.7-2942, and may have detected spectral lines, but they could
not separate the core and extended components. We will measure the
spectrum of the extended (jet?) emission without point source
contamination. This has the possibility of discovering red and
blue-shifted emission lines a la SS433.


Sequence Number: 400162

Title : A CHANDRA OBSERVATION OF THE LONG-DURATION TRANSIENT AND NEUTRON STAR
LOW-MASS X-RAY BINARY KS 1731-260 IN QUIESCENCE
PI: Wijnands
Abstract: The full scientific justification is sent in an email to the Director.
The long-duration transient KS 1731-260 has been active for over a
decade, however, our recent RXTE/PCA observations show that the source
has now gone back in to quiescence. This opens the oppertunity to
study the affects of prolonged accretion onto the neutron star on the
quiescence X-ray properties of a neutron star X-ray transient. This
would be the first time ever that such a study can be performed.
Considerable differences (e.g., a considerable higher luminosity
compared to that of short-duration transients) are expected if the
quiescence properties depend on the time averaged accretion rate in
outburst. We will also obtain an excellent position of the source
allowing the identification of its optical and infrared counter
parts.


Sequence Number: 800178

Title : REOBSERAVTION OF PKS0745-191
PI: Fabian
Abstract: GT observation of this cluster has high background with many flares.
Plots of this background have been shown and discussed, by email, with
Harvey Tananbaum.


Sequence Number: 500197

Title : CHANDRA OBSERVATION OF THE X-RAY AFTERGLOW OF GRB010222, THE BRIGHTEST
GRB OBSERVED BY BEPPOSAX
PI: Piro
Abstract: Chandra observations of X-ray afterglows of GRB provide unique
results. The 1 arcsec positional accuracy, high sensitivity to faint
sources, combined with the unprecedented spectral capabilities of this
instrument will permit: 1)unique and fast counterpart identification
in other wavelenghts, OR a deep study of the property of the GRB site
(host galaxy) to ascertain the nature of dark GRB (i.e. GRB Without
Optical Transient) 2)To study the afterglow spectrum in its early
(bright) and late phases, with the unprecedented potential capability
to detect line spectral features. Both of these goals have been
already demonstrated in our previous observations with CXC (e.g. Piro
et al 2000, Science290,956)


Sequence Number: 400161

Title : CHANDRA OBSERVATIONS OF CYGNUS X-1 IN A RARE, SUSTAINED HIGH/SOFT
STATE
PI: Miller
Abstract: The full SJ is contained in an email to the Director. A clear
High/Soft State was observed in Cyg X-1 between 15 Oct. and 15 Nov.
2000 (mean flux: 0.5-1 Crab, 2-12 keV RXTE ASM). Following a short
Low/Hard state, the mean rate returned to ~1 Crab on 7 Dec. 2000. This
flux and observed spectral softness indicate that Cygnus X-1 has
entered a second sustained High/Soft state episode. This outburst
profile is similar to the 83-day High/Soft state observed May-Aug.
1996 (see http://xte.mit.edu/~rr/cygx1.ps). A Chandra observation of
Cygnus X-1 (PI, Canizares; Cui et al. in prep.) in the Low/Hard state
shows evidence for an Fe K-alpha line, Fe L edges (Cui et al, in
prep). The dynamics and geometry of the L/Hard and H/Soft state are
expected to be markedly different. Measurements of the iron e


Sequence Number: 900066

Title : AN ULTRADEEP SURVEY IN THE CHANDRA DEEP FIELD SOUTH
PI: GIACCONI
Abstract: We propose to exploit the unique combination of angular resolution,
sensitivity and field-of-view of the Chandra ACIS imager to perform
the deepest X-ray survey ever in the well-studied "Chandra Deep Field
South" (CDFS). With a total integration time of 1.5 Msec (request for
this AO: 1 Msec) we reach a 0.5-2 keV flux limit of 2E-17 cgs. We aim
to detect >500 sources, i.e. AGN to z=10, clusters to z=3 and
starburst galaxies to z~1. Simulations based on the existing 130 ksec
observation in the CDFS and realistic source counts and correlation
function models show, that Chandra exposures will not be background or
confusion limited up to 3Msec. We propose to make the Chandra data
public immediately.


Sequence Number: 900066

Title : AN ULTRADEEP SURVEY IN THE CHANDRA DEEP FIELD SOUTH
PI: GIACCONI
Abstract: We propose to exploit the unique combination of angular resolution,
sensitivity and field-of-view of the Chandra ACIS imager to perform
the deepest X-ray survey ever in the well-studied "Chandra Deep Field
South" (CDFS). With a total integration time of 1.5 Msec (request for
this AO: 1 Msec) we reach a 0.5-2 keV flux limit of 2E-17 cgs. We aim
to detect >500 sources, i.e. AGN to z=10, clusters to z=3 and
starburst galaxies to z~1. Simulations based on the existing 130 ksec
observation in the CDFS and realistic source counts and correlation
function models show, that Chandra exposures will not be background or
confusion limited up to 3Msec. We propose to make the Chandra data
public immediately.


Sequence Number: 200125

Title : CAPTURING WR140 AT PERIASTRON WITH THE CHANDRA HETG
PI: Pollock
Abstract: This is a resubmission of our AO2 proposal number 02200508 which was
rejected, despite high scores, because it was mistakenly thought that
XMM would be making similar observations near periastron. In fact,
according to its official WWW visibility tool, XMM is not able to
observe any nearer than two months either side of periastron passage
and possibly not at all. The compelling scientific justification was
given in our original proposal and endorsed by the Peer Review. We are
responding to the Review Panel's recommendation to apply for
Director's Discretionary Time.


Sequence Number: 200124

Title : CAPTURING WR140 AT PERIASTRON WITH THE CHANDRA HETG
PI: Pollock
Abstract: This is a resubmission of our AO2 proposal number 02200508 which was
rejected, despite high scores, because it was mistakenly thought that
XMM would be making similar observations near periastron. In fact,
according to its official WWW visibility tool, XMM is not able to
observe any nearer than two months either side of periastron passage
and possibly not at all. The compelling scientific justification was
given in our original proposal and endorsed by the Peer Review. We are
responding to the Review Panel's recommendation to apply for
Director's Discretionary Time.


Sequence Number: 300053

Title : THE NATURE OF CLASSICAL SYMBIOTIC OUTBURSTS
PI: Charles
Abstract: Symbiotic stars may be the progenitors of the cosmologically important
Type Ia SNe. The high accretion rate onto the white dwarfs (WDs) in
these binaries allows for steady, rather than explosive burning as in
classical novae. The accreted material can therefore remain on the WD,
driving its mass closer to the Chandrasekhar limit, rather than being
blown off in a nova. OR CAN IT? Classical symbiotics experience
outbursts typically every 10 - 20 years, and these events are not
well-understood. After the 1985 outburst of the class prototype, Z
Andromedae (which is also a 28-minute pulsar), it appeared that a
shell of material had been ejected from the WD. This object has
recently outburst again. An X-ray observation within roughly one month
will provide v, T, and density diagnostics deep wit


Sequence Number: 900066

Title : AN ULTRADEEP SURVEY IN THE CHANDRA DEEP FIELD SOUTH
PI: GIACCONI
Abstract: We propose to exploit the unique combination of angular resolution,
sensitivity and field-of-view of the Chandra ACIS imager to perform
the deepest X-ray survey ever in the well-studied "Chandra Deep Field
South" (CDFS). With a total integration time of 1.5 Msec (request for
this AO: 1 Msec) we reach a 0.5-2 keV flux limit of 2E-17 cgs. We aim
to detect >500 sources, i.e. AGN to z=10, clusters to z=3 and
starburst galaxies to z~1. Simulations based on the existing 130 ksec
observation in the CDFS and realistic source counts and correlation
function models show, that Chandra exposures will not be background or
confusion limited up to 3Msec. We propose to make the Chandra data
public immediately.


Sequence Number: 900066

Title : AN ULTRADEEP SURVEY IN THE CHANDRA DEEP FIELD SOUTH
PI: GIACCONI
Abstract: We propose to exploit the unique combination of angular resolution,
sensitivity and field-of-view of the Chandra ACIS imager to perform
the deepest X-ray survey ever in the well-studied "Chandra Deep Field
South" (CDFS). With a total integration time of 1.5 Msec (request for
this AO: 1 Msec) we reach a 0.5-2 keV flux limit of 2E-17 cgs. We aim
to detect >500 sources, i.e. AGN to z=10, clusters to z=3 and
starburst galaxies to z~1. Simulations based on the existing 130 ksec
observation in the CDFS and realistic source counts and correlation
function models show, that Chandra exposures will not be background or
confusion limited up to 3Msec. We propose to make the Chandra data
public immediately.


Sequence Number: 900066

Title : AN ULTRADEEP SURVEY IN THE CHANDRA DEEP FIELD SOUTH
PI: GIACCONI
Abstract: We propose to exploit the unique combination of angular resolution,
sensitivity and field-of-view of the Chandra ACIS imager to perform
the deepest X-ray survey ever in the well-studied "Chandra Deep Field
South" (CDFS). With a total integration time of 1.5 Msec (request for
this AO: 1 Msec) we reach a 0.5-2 keV flux limit of 2E-17 cgs. We aim
to detect >500 sources, i.e. AGN to z=10, clusters to z=3 and
starburst galaxies to z~1. Simulations based on the existing 130 ksec
observation in the CDFS and realistic source counts and correlation
function models show, that Chandra exposures will not be background or
confusion limited up to 3Msec. We propose to make the Chandra data
public immediately.


Sequence Number: 400112

Title : OBSERVATIONS OF A BLACK HOLE CANDIDATE X-RAY TRANSIENT DURING OUTBURST
DECAY
PI: Tomsick
Abstract: We propose to observe the black hole candidate (BHC) X-ray transient
XTE J1550-564 during outburst decay. We have been observing the decay
of the current outburst with RXTE, and, if the source flux continues
its current exponential decay, it will fall below RXTE detection
limits around 2000 July 16. Chandra observations after July 16 will
provide, for the first time, complete coverage of a BHC X-ray
transient decay from outburst to quiescence. Measurements of the flux
and the energy spectrum will address the question of whether there are
major changes in the accretion geometry as the source decays into
quiescence or if the change in X-ray flux is simply due to a drop in
the mass accretion rate. Such information has important implications
for ADAF models, which predict a large change in th


Sequence Number: 400111

Title : OBSERVATIONS OF A BLACK HOLE CANDIDATE X-RAY TRANSIENT DURING OUTBURST
DECAY
PI: Tomsick
Abstract: We propose to observe the black hole candidate (BHC) X-ray transient
XTE J1550-564 during outburst decay. We have been observing the decay
of the current outburst with RXTE, and, if the source flux continues
its current exponential decay, it will fall below RXTE detection
limits around 2000 July 16. Chandra observations after July 16 will
provide, for the first time, complete coverage of a BHC X-ray
transient decay from outburst to quiescence. Measurements of the flux
and the energy spectrum will address the question of whether there are
major changes in the accretion geometry as the source decays into
quiescence or if the change in X-ray flux is simply due to a drop in
the mass accretion rate. Such information has important implications
for ADAF models, which predict a large change in th


Sequence Number: 700266

Title : X-RAYING THE BRIGHTEST AGN IN THE SKY WITH THE CHANDRA GRATINGS
PI: Fruscione
Abstract: We propose to observe the BLLac Mrk421 as a TOO whenever it reaches an
ultra-high state (2-12 keV flux greater than 20 mCrab). Currenty,
Mrk421 is undergoing a huge flare with a peak flux of 43 mCrab, making
it the brightest AGN in the sky. The flux has reached such a high
level (which is a factor of ~3 higher that the average) at only one
other time in the past 4 years. High spectral resolution Chandra HETG
and LETG X-ray observations of an AGN in such a bright state would
represent an extraordinary opportunity to study in great detail not
only the gaseous environment surrounding the nucleus, but also the
physical state of possible intervening absorption systems. We we will
be allowed to measure with extreme precision, the ionization degree,
the column density, the temperature, the densi


Sequence Number: 700265

Title : X-RAYING THE BRIGHTEST AGN IN THE SKY WITH THE CHANDRA GRATINGS
PI: Fruscione
Abstract: We propose to observe the BLLac Mrk421 as a TOO whenever it reaches an
ultra-high state (2-12 keV flux greater than 20 mCrab). Currenty,
Mrk421 is undergoing a huge flare with a peak flux of 43 mCrab, making
it the brightest AGN in the sky. The flux has reached such a high
level (which is a factor of ~3 higher that the average) at only one
other time in the past 4 years. High spectral resolution Chandra HETG
and LETG X-ray observations of an AGN in such a bright state would
represent an extraordinary opportunity to study in great detail not
only the gaseous environment surrounding the nucleus, but also the
physical state of possible intervening absorption systems. We we will
be allowed to measure with extreme precision, the ionization degree,
the column density, the temperature, the densi


Sequence Number: 300041

Title : CHANDRA HETG SPECTROSCOPY OF EX HYDRAE
PI: Howell
Abstract: EX Hya is an eclipsing intermediate polar-type CV with strong H- and
He-like K alpha emission lines of Mg, Si, S, Ar, and Fe emission lines
of Ne VII-VIII and Fe XVIII-XXIII in the EUV spectrum. The density of
the emitting plasma of EX Hya is ~ 10^13 to 10^15 cm^-3, more than an
order of magnitude greater than that of the corona of cool stars. We
propose a 60 ks Chandra HETG spectrum of EX Hya to: (1) constrain the
run of density with temperature (thereby constraining models of the
accretion column), (2) measure the amount of fluor- escence from the
irradiated surface of the WD, (3) measure elemental abundances
(controversial from the ASCA spectrum), and (4) spectroscopically
measure the density of the emitting plasma (via line ratios of He-like
O VII, Ne IX, Mg XI, Si XIII, S XV, Ar XVII


Sequence Number: 400110

Title : CHANDRA ACIS/LETG OBSERVATIONS OF THE LEAST ABSORBED X-RAY NOVA: XTE
J1118+48
PI: McClintock
Abstract: SCIENCE RATIONALE We propose Chandra grating observations of the X-ray
nova XTE J1118+48. The source was discovered in late March of this
year by the All-Sky Monitor on RXTE (IAUC 7389) and it was identified
optically shortly thereafter (IAUC 7390). This probable black-hole
source has a unique and important characteristic: It is the only X-ray
nova (XRN) located at high galactic latitude (b=+62 deg). Thus it has
by far the lowest extinction of any XRN, making it an exciting target
for grating studies with Chandra. The column density out of the plane
in this direction is log(NH) = 20.1 (Dickey and Lockman 1990, A&AS 28,
215). At energies <1 keV very little is known about the properties of
X-ray binaries--especially XRN--because nearly all sources lie at low
galactic latitude and have high


Sequence Number: 700202

Title : STUDIES OF RADIO JETS AND THE NARROW LINE REGIONS
PI: Wilson
Abstract: The X-ray emission of radio jets and of the narrow line regions of
active galaxies will be investigated with AXAF. Images and spectra
will be obtained to define the morphologies, X-ray powers, emission
mechanisms and physical conditions of both unresolved nuclear and
extended emission. Detection of non-thermal X-rays (inverse Compton or
synchrotron emission) will probe the properties of the magnetic fields
and cosmic ray spectra. If thermal X-ray emission is detected, the
density, temperature and chemical abundances of hot gas can be derived
and the relationship to other components (radio emission, narrow line
region) studied. Hot gas can be associated with hot radiatively driven
winds, shocks driven by mass outflow or cooling accretion flows.


Sequence Number: 400093

Title : TOO OBSERVATION OF THE RELATIVISTIC JET SOURCE CYGNUS X-3
PI: McCollough
Abstract: In Feb 1997, during a major radio flare in Cyg X-3, a 120
milli-arcsecond radio jet, which exhibited relativistic (~0.9 c)
expansion, was observed. Although Chandra would be unable to resolve
such a jet, a high-resolution spectra taken during a major flare may
contain Doppler shifted emission lines revealing the presence of an
x-ray jet. Observations of Cyg X-3 during such a flare offers the very
interesting possibility of studying the dynamics of jet formation and
propagation through the study of emission lines with the high spectral
resolution afforded by the HETG/ACIS SI configuration. The 20 ks
length of the observation permits coverage over one complete 4.8 hour
cycle. A second 20 ks observation 3 days later provides data for
studying the spectral evolution that surely accompanies su


Sequence Number: 400092

Title : TOO OBSERVATION OF THE RELATIVISTIC JET SOURCE CYGNUS X-3
PI: McCollough
Abstract: In Feb 1997, during a major radio flare in Cyg X-3, a 120
milli-arcsecond radio jet, which exhibited relativistic (~0.9 c)
expansion, was observed. Although Chandra would be unable to resolve
such a jet, a high-resolution spectra taken during a major flare may
contain Doppler shifted emission lines revealing the presence of an
x-ray jet. Observations of Cyg X-3 during such a flare offers the very
interesting possibility of studying the dynamics of jet formation and
propagation through the study of emission lines with the high spectral
resolution afforded by the HETG/ACIS SI configuration. The 20 ks
length of the observation permits coverage over one complete 4.8 hour
cycle. A second 20 ks observation 3 days later provides data for
studying the spectral evolution that surely accompanies su


Sequence Number: 300037

Title : BZ CAM - A TRANSIENT SUPERSOFT X-RAY SOURCE?
PI: Di Stefano
Abstract: BZ Cam is a binary with a 221 min. period. It contains an accreting
white dwarf and a 0.3-0.4 solar mass main-sequence donor. BZ Cam
belongs to the group of variables called VY Scl stars. Most of the
time it spends at V=12.7 mag, but during low states it has V=14.3 mag.
BZ Cam is surrounded by a faint emission nebula (AA 181, 373).
Photoionization by a canonical cataclysmic variable cannot account for
the nebular excitation (emission line ratios). The proposed ACIS-S
observation will test the hypothesis that BZ Cam, like V751 Cyg (A&A
343, 183) and the canonical supersoft source (SSS) RX J0513.9-6951,
emits luminous supersoft X-rays during its optical low-state. If
supersoft X-rays could be detected, it would have 2 major
implications: (1) Discovery of new object class: VY Scl stars = tra


Sequence Number: 500093

Title : SURVEYING THE AFTERMATH OF A STARQUAKE
PI: Helfand
Abstract: The Vela pulsar underwent a sudden spinup yesterday morning (Jan 16.3
UT), the largest such event in the thirty years since its discovery.
We propose to take advantage of this fortuitous event by observing the
pulsar and its surrounding synchrotron nebula three times with the
Chandra HRC with the goals of 1) discriminating among models for such
spinup events, 2) constraining the equation of state of neutron star
matter, and 3) monitoring the effects of the event on the surrounding
synchrotron nebula. The Vela nebula will produce a count rate of ~3.8
c/s in the HRC-I, and the pulsar's pulsed emission should yield ~ .15
ct/s. Observations of 50 ksec duration will thus yield sensitivities
to a 1% change in the nebula (4 sigma) and a change of 15% in any of
20 phase bins for the pulse (3 sigm


Sequence Number: 300037

Title : BZ CAM - A TRANSIENT SUPERSOFT X-RAY SOURCE?
PI: Di Stefano
Abstract: BZ Cam is a binary with a 221 min. period. It contains an accreting
white dwarf and a 0.3-0.4 solar mass main-sequence donor. BZ Cam
belongs to the group of variables called VY Scl stars. Most of the
time it spends at V=12.7 mag, but during low states it has V=14.3 mag.
BZ Cam is surrounded by a faint emission nebula (AA 181, 373).
Photoionization by a canonical cataclysmic variable cannot account for
the nebular excitation (emission line ratios). The proposed ACIS-S
observation will test the hypothesis that BZ Cam, like V751 Cyg (A&A
343, 183) and the canonical supersoft source (SSS) RX J0513.9-6951,
emits luminous supersoft X-rays during its optical low-state. If
supersoft X-rays could be detected, it would have 2 major
implications: (1) Discovery of new object class: VY Scl stars = tra


Sequence Number: 570470

Title : FOLLOW-UP OBSERVATIONS OF SN1999GI IN NGC 3184
PI: Schlegel
Abstract: Type II supernovae may all be X-ray sources but differences in
behavior are becoming visible: normal SN II's fade quickly while the
abnormal SN IIn's last for months, perhaps years. These suppositions
are based upon very limited statistics: 2 normal SN II's and about 4-6
SN IIn's. The turn-on times are unknown, as are the half-lives. Two
normal SN II's observed in the X-ray band are SN1980K (Canizares et
al. 1982) and SN1999em (Fox & Lewin 1999, IAU Circ 7318). The turn-on
time of these SNe appear to be nearly immediate. Radio and X-ray
emission should be correlated, yet are not: SN1980K was an early radio
source; SN1999em has not yet been detected. But a correlation with
radio emission must be suspect with so little data. SN1999gi,the
target of this TOO, represents a potential third norm


Sequence Number: 100011

Title : NULL
PI: WAITE
Abstract: NULL


Sequence Number: 100011

Title : NULL
PI: WAITE
Abstract: NULL


Sequence Number: 100010

Title : NULL
PI: WAITE
Abstract: NULL


Sequence Number: 201085

Title : Coordinated calibration observation of Capella with Hitomi
PI: Petre
Abstract: Hitomi is just about to start its calibration phase. One of the most
critical SXS calibration targets is Capella, which will be used to
verify the low energy spectral resolution, line spread function, and
effective area. We request a coordinated Chandra HETG observation to
provide an absolute reference. Comparison with the well-calibrated
HETG will allow the SXS team to separate detector properties from
astrophysical effects. A simultaneous observation is needed to provide
an external measurement of the flux of Capella's lines, which are
known to vary in flux. Capella is the only Hitomi calibration source
for which a coordinated Chandra observation will be requested. A 60 ks
observation will allow us to cover entirely at least one of the 30 ks
pointings that Hitomi plans to perform on Capella during the
aforementioned window.


Sequence Number: 201085

Title : Coordinated calibration observation of Capella with Hitomi
PI: Petre
Abstract: Hitomi is just about to start its calibration phase. One of the most
critical SXS calibration targets is Capella, which will be used to
verify the low energy spectral resolution, line spread function, and
effective area. We request a coordinated Chandra HETG observation to
provide an absolute reference. Comparison with the well-calibrated
HETG will allow the SXS team to separate detector properties from
astrophysical effects. A simultaneous observation is needed to provide
an external measurement of the flux of Capella's lines, which are
known to vary in flux. Capella is the only Hitomi calibration source
for which a coordinated Chandra observation will be requested. A 60 ks
observation will allow us to cover entirely at least one of the 30 ks
pointings that Hitomi plans to perform on Capella during the
aforementioned window.


Sequence Number: 401687

Title : A second HLX-1-like object in CXO J122518.6+144545
PI: Heida
Abstract: Intermediate mass black holes are crucial as building blocks for
supermassive BHs, but observational evidence for their existence is
still scarce. The brightest ULXs may be good IMBH candidates: the
strongest case is ESO 243-49 HLX-1 (Farrell et al. 2009), an X-ray
source that reaches a luminosity of more than 10E42 erg/s. It is
thought to host a BH of ~20,000 solar masses. Up until now, HLX-1 is
the only known object of its kind. Most candidate ULXs with comparable
luminosities have turned out to be background AGN. Finding more HLX-1
like objects would be an important step forward in the search for
IMBHs. We have investigated the X-ray source CXOJ122518.6+144545
(J1225; Jonker et al. 2010) with Chandra. It was found in an
observation from 2008, at a luminosity of ~2E41 erg/s, making it the
second most luminous ULX after HLX-1. We did not detect the source in
November 2012 and in April and July 2014, but in our last observation
on November 20 it was again visible at ~5E40 erg/s.


Sequence Number: 200829

Title : X-ray irradiation and evaporation of a super-Earth exoplanet
PI: Wheatley
Abstract: The recent discovery that the super-Earth exoplanet 55 Cnc e transits
its 6th mag star provides the exciting opportunity to study the upper
atmosphere of a super-Earth for the first time. Our team has secured
HST DDT with the aim of searching for hydrogen escaping the planet (by
measuring absorption in Ly-alpha through two transits). The planet
density suggests that it may be composed largely of water, in which
case hydrogen evaporation may be expected from a photo-disassociating
super-critical ocean. We propose Chandra observations to measure the
X-ray flux of the host star at the time of both HST observations (on
Mar 7 and Apr 5). Exoplanet evaporation is thought to be driven by
X-ray irradiation, and combined X-ray/UV measurements are required to
measure the mass loss rate and determine the evaporation efficiency.
By measuring X-ray irradiation and the resulting evaporation through
two transits we can begin to study the response of a super-Earth
atmosphere to varying irradiation.


Sequence Number: 401296

Title : The peculiar BH transient MAXI J1659-152: jet-only emission in
quiescence?
PI: Jonker
Abstract: The BH transient, MAXIJ1659-152, started decaying towards quiescence
before all X-ray observatories could no longer observe the source due
to Sun constraints. However, recent Swift observations (Yang et al.
2011 ATel 3201) found the source at a flux of 2E-11 cgs. This is
peculiar as all transient BHs except SwiftJ1753 decayed quickly.
During the last Swift observation the source was still at that flux
level and evidence for a line-like feature at 7.4 keV was found (by
us). Perhaps the source is in fact in quiescence, and what we observe
is X-ray emission from the jet impact region, the 7.4 keV line could
then be due to blueshifted Fe emission. A similar effect has been seen
in SS433 (Migliari et al. 2002). Furthermore, the source X-ray
position determined by Swift is somewhat shifted wrt the best known
VLBI radio emission. However, a short 1 ks Chandra observation will
shed light on this.


Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec


Sequence Number: 200461

Title : A(nother) Star is Born: the Early Evolution of a Pre-main Sequence
Accretion Burst
PI: Kastner
Abstract: Accretion processes produce X-ray emission in a wide variety of
astrophysical environments, yet the link between pre-main sequence
(PMS) star accretion and X-ray emission remains tenuous at best.
Undoubtedly the most convincing example of accretion-driven PMS X-ray
emission is that of V1647 Ori; Chandra observations obtained over the
(two-year) duration of the optical/IR outburst of this PMS star
revealed that its X-ray flux and hardness closely tracked the dramatic
rise and subsequent decline of its accretion luminosity (Kastner et
al. 2004, Nature, 430, 429 and 2006, ApJ, 648, L43). These results for
V1647 Ori suggest that X-ray emission from erupting low-mass, PMS
stars is diagnostic of the degree of star-disk magnetic field
reorganization during major ("FUor"- or "EXor"-type) accretion events.
Prompt post-outburst observations of additional erupting PMS stars are
required to test this hypothesis.


Sequence Number: 300182

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.


Sequence Number: 300181

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.


Sequence Number: 300180

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.


Sequence Number: 200365

Title : Monitoring the X-ray Emission of the Newly Erupted EXor-type V1118
Ori
PI: Audard
Abstract: The origin of the X-ray emission in young, accreting stars remains a
mystery. Accretion seems the dominant mechanism in TW Hya (cool
plasma; high densities). However, other moderately accreting classical
T Tauri stars show high temperatures and low densities. Eruptive young
stars (FUors and EXors) are the key to understanding the importance of
accretion for X-rays since they suddenly display increased accretion
rates from 1E-7 to 1E-4 Msol/year. FUors display brighter and longer
outbursts than EXors but they are far less frequent. Recently, the
(FUor-type) V1647 Ori erupted and triggered an international
observation campaign. In X-rays, Kastner et al. (2004) reported a
30-fold flux increase from the pre-outburst flux, indicating that the
high-energy emission in young stars can increase dramatically due to
the rapid increase of accretion rates in FUor/EXor outbursts. However,
the flux rapidly dropped in the steady high state.


Sequence Number: 200364

Title : Monitoring the X-ray Emission of the Newly Erupted EXor-type V1118
Ori
PI: Audard
Abstract: The origin of the X-ray emission in young, accreting stars remains a
mystery. Accretion seems the dominant mechanism in TW Hya (cool
plasma; high densities). However, other moderately accreting classical
T Tauri stars show high temperatures and low densities. Eruptive young
stars (FUors and EXors) are the key to understanding the importance of
accretion for X-rays since they suddenly display increased accretion
rates from 1E-7 to 1E-4 Msol/year. FUors display brighter and longer
outbursts than EXors but they are far less frequent. Recently, the
(FUor-type) V1647 Ori erupted and triggered an international
observation campaign. In X-rays, Kastner et al. (2004) reported a
30-fold flux increase from the pre-outburst flux, indicating that the
high-energy emission in young stars can increase dramatically due to
the rapid increase of accretion rates in FUor/EXor outbursts. However,
the flux rapidly dropped in the steady high state.


Sequence Number: 100052

Title : Chandra by Chandra
PI: Drake
Abstract: A 75ks Chandra observation of the Moon can dramatically increase our
knowledge of lunar geochemistry and provide strong tests of models of
lunar formation and evolution. By resolving fluorescent lines of O,
Mg, Al, and Si, Chandra can provide the first detailed surface
abundance maps of these elements that dominate the crustal and mantle
mineralogy. The results will: (i) provide direct bulk surface
abundances crucial for lunar formation models; (ii) test our
understanding of the Moon's history and crustal evolution through
detailed comparison of abundance ratios within mare, between
geologically diverse lunar surface features, and in craters and ejecta
blankets of different scale; (iii) firmly establish earth orbit X-ray
observation as a powerful means of investigating solar system rocky
bodies; (iv) help prepare for future (c.2005) SMART-1 in-situ lunar
fluorescence measurements; (v) produce high resolution X-ray lunar
images that will likely have significant public appeal.


Sequence Number: 100052

Title : Chandra by Chandra
PI: Drake
Abstract: A 75ks Chandra observation of the Moon can dramatically increase our
knowledge of lunar geochemistry and provide strong tests of models of
lunar formation and evolution. By resolving fluorescent lines of O,
Mg, Al, and Si, Chandra can provide the first detailed surface
abundance maps of these elements that dominate the crustal and mantle
mineralogy. The results will: (i) provide direct bulk surface
abundances crucial for lunar formation models; (ii) test our
understanding of the Moon's history and crustal evolution through
detailed comparison of abundance ratios within mare, between
geologically diverse lunar surface features, and in craters and ejecta
blankets of different scale; (iii) firmly establish earth orbit X-ray
observation as a powerful means of investigating solar system rocky
bodies; (iv) help prepare for future (c.2005) SMART-1 in-situ lunar
fluorescence measurements; (v) produce high resolution X-ray lunar
images that will likely have significant public appeal.


Sequence Number: 500414

Title : SN2002ic and its Circumstellar Medium
PI: Hughes
Abstract: Supernova (SN) 2002ic (IAUC 8019) is the first thermonuclear or Type
Ia SN ever to show hydrogen in its spectrum (IAUC 8151). Hamuy et al
(astro-ph/0306270) argue that the H alpha emission of the SN arises
from a dense circumstellar medium (CSM), which itself was the result
of pre-SN mass loss from a massive asymptotic giant branch star that
was the companion to the white dwarf that exploded as the SN. This
result could have wide implications for the origin of SNe Ia and their
cosmological use. This study is based on observations taken between
November and February; our more recent VLT data from July continue to
show strong H alpha emission. Radio emission has not been detected
(IAUC 8157), which can be explained if there is substantial free-free
absorption in the CSM gas. Hard X-ray observations are the most
sensitive probe of the CSM surrounding SN Ia; here we propose X-ray
observations of SN2002ic to detect the shocked CSM and confirm the
high mass loss rate of the progenitor.


Sequence Number: 400269

Title : AN ACIS LOOK AT MACHO-99-BLG-22:AN INTERMEDIATE MASS BLACK HOLE ON OUR
DOORSTEP?
PI: Reynolds
Abstract: We request a 20ks ACIS-S observation at the position of the longest
ever detected microlensing event, MACHO-99-BLG-22. A likelyhood
analysis of the lensing event shows that the lens is either a stellar
mass black hole (BH) in the Galactic bulge, *or* an intermediate mass
BH about 500pc from us. Constraints from an old ROSAT-PSPC observation
are uninteresting (F_X<2*10^-13 erg/cm^2/s). However, Chandra will be
able to easily detect radiatively-efficient Bondi-Hoyle accretion onto
the BH. Even in the "worst case" of accretion from the hot ISM with a
column density of 1e21/cm^2 and a bolometric correction of 10, we
would expect to detect 20 photons. On the other hand, it is very
unlikely that a stellar mass BH in the bulge would be detectable. The
requested observation, therefore, provides a powerful way of
determining whether the lensing object really is an intermediate mass
BH on our doorstep.


Sequence Number: 500299

Title : SN2001IG: DETECTING A MASS LOSS PHASE?
PI: Schlegel
Abstract: The X-ray emission of supernovae is a young field with relatively
little data. X-rays provide information about the circumstellar ejecta
as the outgoing shock runs into matter from previous phases of mass
loss. A reverse shock is created which generates low-energy X-rays (~1
keV) while the outgoing shock generates harder events. The X-rays
probe the circumstellar matter and are expected to provide measures of
abundances in spectral lines. The X-ray light curve (LC) additionally
provides a measure of the matter distribution (Ref for SN: Schlegel
1995, Reports on Prog in Physics, 58, 1375). The radio LC of SN1979C
has been interpreted as revealing waves of mass loss (Weiler et al.
1992, ApJ, 399, 672) from the progenitor. No other SN has shown such
behavior prior to the recent increase in the radio LC of SN2001ig. We
expect the hard and soft X-rays to behave differently, directly
testing shock/reverse shock theory.


Sequence Number: 400245

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400244

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400243

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400242

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400241

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 400240

Title : A FAINT NEUTRON STAR SOFT X-RAY TRANSIENT RETURNING TO QUIESCENCE
PI: Jonker
Abstract: Approx 10 SXTs like SAXJ1808.4-3658 form a class of faint SXTs,
calculations show that the NS magnetic field will not be buried in
these systems. We propose to obtain three observations of a faint SXT
as it returns to quiescence. Monitoring observations will allow us to
observe the transition from a spectrally hard state in outburst to a
soft spectral state in quiescence. To find out which emission
mechanism is responsible for the low-level X-ray emission, it is
crucial to get good 0.1-8 keV spectra and to identify at which
luminosity the transition from hard to soft takes place. For this
study the low N_H of this source is vital. Given a neutron star
magnetic field strength, for lower mass accretion rates (unaccessible
for RXTE) the magnetosphere will be larger and the polar caps onto
which magnetically channelled matter accretes smaller, resulting in
larger pulsed fractions. Observations with ACIS-S in CC mode will
allow us to search for pulsations at frequencies less than 166 Hz.


Sequence Number: 100033

Title : SPECTROSCOPIC IMAGING OF CHARGE EXCHANGE X-RAY EMISSION FROM COMET
C/2002 C1
PI: Dennerl
Abstract: Comet C/2002 C1, discovered on February 1, 2002, is predicted to be as
bright as 4 - 5 mag when it will become observable with Chandra from
April 10, 2002. We propose to utilize this opportunity for direct
spectroscopic imaging with ACIS-S. This has never been done for such a
bright comet. Thanks to a favorable observing geometry, we can apply a
novel observing technique: as the comet will slowly move along the
comet-Sun line, an automatic scan of the x-ray emission properties
will be provided along this direction, where the charge exchange model
predicts a characteristic spectral evolution, which could, however,
not be tested so far. While previous Chandra images and spectra of
comets suffer from low photon statistics, we expect to get about 40
times more photons than from C/LINEAR S4. This will allow us to
utilize the full spectral and spatial resolution of Chandra. A
detailed Scientific Justification is provided in the attached
Postscript file.


Sequence Number: 500290

Title : AN EARLY OBSERVATION OF A NEARBY SUPERNOVA
PI: Schlegel
Abstract: The X-ray emission of supernovae is a young field with relatively
little data. The possible connection of supernovae with GRBs has been
tantalizing since the occurrence of SN1998bw. The debate over that
source continues. Observations of SN2002ap may go a long way to
settling some of the debate. In addition, the X-ray emission of Type
Ic supernova other than SN1998bw is based on the single detection of
SN1994I in M51. X-rays provide information about the circumstellar
ejecta as the out- going shock runs into matter from previous phases
of mass loss. A reverse shock is created which generates low-energy
X-rays (~1 keV) while the outgoing shock generates harder events. The
X-rays probe the circumstellar matter and will provide measures of
abundances. The X-ray light curve provides a measure of the matter
distribution. (Ref for SN: Schlegel 1995, Reports Prog in Physics, 58,
1375)


Sequence Number: 500289

Title : AN EARLY OBSERVATION OF A NEARBY SUPERNOVA
PI: Schlegel
Abstract: The X-ray emission of supernovae is a young field with relatively
little data. The possible connection of supernovae with GRBs has been
tantalizing since the occurrence of SN1998bw. The debate over that
source continues. Observations of SN2002ap may go a long way to
settling some of the debate. In addition, the X-ray emission of Type
Ic supernova other than SN1998bw is based on the single detection of
SN1994I in M51. X-rays provide information about the circumstellar
ejecta as the out- going shock runs into matter from previous phases
of mass loss. A reverse shock is created which generates low-energy
X-rays (~1 keV) while the outgoing shock generates harder events. The
X-rays probe the circumstellar matter and will provide measures of
abundances. The X-ray light curve provides a measure of the matter
distribution. (Ref for SN: Schlegel 1995, Reports Prog in Physics, 58,
1375)


Sequence Number: 500288

Title : AN EARLY OBSERVATION OF A NEARBY SUPERNOVA
PI: Schlegel
Abstract: The X-ray emission of supernovae is a young field with relatively
little data. The possible connection of supernovae with GRBs has been
tantalizing since the occurrence of SN1998bw. The debate over that
source continues. Observations of SN2002ap may go a long way to
settling some of the debate. In addition, the X-ray emission of Type
Ic supernova other than SN1998bw is based on the single detection of
SN1994I in M51. X-rays provide information about the circumstellar
ejecta as the out- going shock runs into matter from previous phases
of mass loss. A reverse shock is created which generates low-energy
X-rays (~1 keV) while the outgoing shock generates harder events. The
X-rays probe the circumstellar matter and will provide measures of
abundances. The X-ray light curve provides a measure of the matter
distribution. (Ref for SN: Schlegel 1995, Reports Prog in Physics, 58,
1375)


Sequence Number: 300088

Title : TOO OBSERVATIONS OF THE RECURRENT NOVA IM NORMAE IN OUTBURST
PI: Starrfield
Abstract: IM Nor is a Recurrent Nova (RN) discovered in outburst on 10 Jan 02.
It rose to V~7.7 on 16 Jan suggesting that it was caught at the
beginning of its outburst. Based on its first outburst in 1920 (near
maximum for ~ 100 days), it is one of only two SLOW RN. While CHANDRA
observed another RN with ACIS-S (CI Aql in 2000), the resulting
spectrum was weak. However, CI Aql was fainter at maximum and the
spectrum was taken after it had returned to quiescence. RN may be
progenitors of SN Ia suggesting that we need to obtain as much
information as we can about their properties. We, therefore, propose a
5 ksec ACIS-S observation to see if it is bright in X-rays followed by
a 25 kse c HRC-S+LETG spectrum to study the ejecta. The ACIS-S
spectrum will show either emission lines from a hot gas (seen in V382
Vul) or a hot continuum from a white dwarf atmosphere (V1494 Aql).
Neither of these resemble the spectrum of a dwarf nova (WZ Sge).


Sequence Number: 700614

Title : CHANDRA MONITORING OF A MICROLENSING EVENT IN MG J0414+0534
PI: Chartas
Abstract: Recent Chandra monitoring of the gravitational lens (GL) system MG
J0414+0534 indicate that images C and B are possibly undergoing
microlensing events. The microlensing event in image B is of
particular interest since it is accompanied by a five-fold increase of
the equivalent width of a reprocessed narrow Fe Ka line in the
spectrum of image B. This sudden increase can be explained with a
caustic crossing that selectively enhances a strip of the reflection
emission region of the accretion disk. The main goal of the proposed
DDT observations is to directly probe the various emission regions of
an accretion disk from scales of a few hundred gravitational radii
down to the event horizon of the black hole. We expect to achieve this
goal by monitoring changes in the line energy, intensity, and profile
of an Fe Ka line in image B as a magnification caustic is traversing
the accretion disk of the distant z = 2.64 radio loud quasar MG
J0414+0534.


Sequence Number: 700613

Title : CHANDRA MONITORING OF A MICROLENSING EVENT IN MG J0414+0534
PI: Chartas
Abstract: Recent Chandra monitoring of the gravitational lens (GL) system MG
J0414+0534 indicate that images C and B are possibly undergoing
microlensing events. The microlensing event in image B is of
particular interest since it is accompanied by a five-fold increase of
the equivalent width of a reprocessed narrow Fe Ka line in the
spectrum of image B. This sudden increase can be explained with a
caustic crossing that selectively enhances a strip of the reflection
emission region of the accretion disk. The main goal of the proposed
DDT observations is to directly probe the various emission regions of
an accretion disk from scales of a few hundred gravitational radii
down to the event horizon of the black hole. We expect to achieve this
goal by monitoring changes in the line energy, intensity, and profile
of an Fe Ka line in image B as a magnification caustic is traversing
the accretion disk of the distant z = 2.64 radio loud quasar MG
J0414+0534.


Sequence Number: 700611

Title : CHANDRA MONITORING OF A MICROLENSING EVENT IN MG J0414+0534
PI: Chartas
Abstract: Recent Chandra monitoring of the gravitational lens (GL) system MG
J0414+0534 indicate that images C and B are possibly undergoing
microlensing events. The microlensing event in image B is of
particular interest since it is accompanied by a five-fold increase of
the equivalent width of a reprocessed narrow Fe Ka line in the
spectrum of image B. This sudden increase can be explained with a
caustic crossing that selectively enhances a strip of the reflection
emission region of the accretion disk. The main goal of the proposed
DDT observations is to directly probe the various emission regions of
an accretion disk from scales of a few hundred gravitational radii
down to the event horizon of the black hole. We expect to achieve this
goal by monitoring changes in the line energy, intensity, and profile
of an Fe Ka line in image B as a magnification caustic is traversing
the accretion disk of the distant z = 2.64 radio loud quasar MG
J0414+0534.


Sequence Number: 700610

Title : CHANDRA MONITORING OF A MICROLENSING EVENT IN MG J0414+0534
PI: Chartas
Abstract: Recent Chandra monitoring of the gravitational lens (GL) system MG
J0414+0534 indicate that images C and B are possibly undergoing
microlensing events. The microlensing event in image B is of
particular interest since it is accompanied by a five-fold increase of
the equivalent width of a reprocessed narrow Fe Ka line in the
spectrum of image B. This sudden increase can be explained with a
caustic crossing that selectively enhances a strip of the reflection
emission region of the accretion disk. The main goal of the proposed
DDT observations is to directly probe the various emission regions of
an accretion disk from scales of a few hundred gravitational radii
down to the event horizon of the black hole. We expect to achieve this
goal by monitoring changes in the line energy, intensity, and profile
of an Fe Ka line in image B as a magnification caustic is traversing
the accretion disk of the distant z = 2.64 radio loud quasar MG
J0414+0534.


Sequence Number: 700609

Title : CHANDRA MONITORING OF A MICROLENSING EVENT IN MG J0414+0534
PI: Chartas
Abstract: Recent Chandra monitoring of the gravitational lens (GL) system MG
J0414+0534 indicate that images C and B are possibly undergoing
microlensing events. The microlensing event in image B is of
particular interest since it is accompanied by a five-fold increase of
the equivalent width of a reprocessed narrow Fe Ka line in the
spectrum of image B. This sudden increase can be explained with a
caustic crossing that selectively enhances a strip of the reflection
emission region of the accretion disk. The main goal of the proposed
DDT observations is to directly probe the various emission regions of
an accretion disk from scales of a few hundred gravitational radii
down to the event horizon of the black hole. We expect to achieve this
goal by monitoring changes in the line energy, intensity, and profile
of an Fe Ka line in image B as a magnification caustic is traversing
the accretion disk of the distant z = 2.64 radio loud quasar MG
J0414+0534.


Sequence Number: 100027

Title : X-RAY EMISSION FROM COMET 10P/BORRELLY DURING THE DEEP SPACE 1
ENCOUNTER
PI: Dennerl
Abstract: X-ray emission from comets is now a well established phenomenon.
During the last years a lot of evidence has emerged that the dominant
mechanism is charge exchange between heavy solar wind ions and
cometary neutrals. The recent Chandra ACIS-S observation of Comet
C/1999 S4 (LINEAR) has provided the final proof. Measurements of solar
wind parameters, however, have never been made sufficiently near to a
comet to allow a direct comparison with the X-ray flux. The recent
decision of NASA to extend the Deep Space 1 mission for a rendezvous
with comet 19P/Borrelly in Sept 2001 opens, for the first time ever,
the unique opportunity to combine in-situ measurements of the solar
wind properties at a comet with simultaneous X-ray observations. This
RfO is submitted as a request for DDT since the dec


Sequence Number: 100027

Title : X-RAY EMISSION FROM COMET 10P/BORRELLY DURING THE DEEP SPACE 1
ENCOUNTER
PI: Dennerl
Abstract: X-ray emission from comets is now a well established phenomenon.
During the last years a lot of evidence has emerged that the dominant
mechanism is charge exchange between heavy solar wind ions and
cometary neutrals. The recent Chandra ACIS-S observation of Comet
C/1999 S4 (LINEAR) has provided the final proof. Measurements of solar
wind parameters, however, have never been made sufficiently near to a
comet to allow a direct comparison with the X-ray flux. The recent
decision of NASA to extend the Deep Space 1 mission for a rendezvous
with comet 19P/Borrelly in Sept 2001 opens, for the first time ever,
the unique opportunity to combine in-situ measurements of the solar
wind properties at a comet with simultaneous X-ray observations. This
RfO is submitted as a request for DDT since the dec


Sequence Number: 100027

Title : X-RAY EMISSION FROM COMET 10P/BORRELLY DURING THE DEEP SPACE 1
ENCOUNTER
PI: Dennerl
Abstract: X-ray emission from comets is now a well established phenomenon.
During the last years a lot of evidence has emerged that the dominant
mechanism is charge exchange between heavy solar wind ions and
cometary neutrals. The recent Chandra ACIS-S observation of Comet
C/1999 S4 (LINEAR) has provided the final proof. Measurements of solar
wind parameters, however, have never been made sufficiently near to a
comet to allow a direct comparison with the X-ray flux. The recent
decision of NASA to extend the Deep Space 1 mission for a rendezvous
with comet 19P/Borrelly in Sept 2001 opens, for the first time ever,
the unique opportunity to combine in-situ measurements of the solar
wind properties at a comet with simultaneous X-ray observations. This
RfO is submitted as a request for DDT since the dec


Sequence Number: 100027

Title : X-RAY EMISSION FROM COMET 10P/BORRELLY DURING THE DEEP SPACE 1
ENCOUNTER
PI: Dennerl
Abstract: X-ray emission from comets is now a well established phenomenon.
During the last years a lot of evidence has emerged that the dominant
mechanism is charge exchange between heavy solar wind ions and
cometary neutrals. The recent Chandra ACIS-S observation of Comet
C/1999 S4 (LINEAR) has provided the final proof. Measurements of solar
wind parameters, however, have never been made sufficiently near to a
comet to allow a direct comparison with the X-ray flux. The recent
decision of NASA to extend the Deep Space 1 mission for a rendezvous
with comet 19P/Borrelly in Sept 2001 opens, for the first time ever,
the unique opportunity to combine in-situ measurements of the solar
wind properties at a comet with simultaneous X-ray observations. This
RfO is submitted as a request for DDT since the dec


Sequence Number: 300064

Title : WZ SGE IN OUTBURST TEN YEARS EARLY: II THE X-RAY EMISSION
PI: Wheatley
Abstract: This is the second half of the WZ Sge DDT proposal. In the first we
requested HRC-S/LETG spectrscopy of the EUV emission. Here we request
ACIS-S observations of the (probably weak) X-ray emission. The X-ray
emission is likely to be supressed below its usual quiescent level
during the outburst, as the emission is thought to switch to the EUV.
However, WZ Sge has never been observed in X-rays during outburst.


Sequence Number: 300063

Title : WZ SGE IN OUTBURST TEN YEARS EARLY: II THE X-RAY EMISSION
PI: Wheatley
Abstract: This is the second half of the WZ Sge DDT proposal. In the first we
requested HRC-S/LETG spectrscopy of the EUV emission. Here we request
ACIS-S observations of the (probably weak) X-ray emission. The X-ray
emission is likely to be supressed below its usual quiescent level
during the outburst, as the emission is thought to switch to the EUV.
However, WZ Sge has never been observed in X-rays during outburst.


Sequence Number: 300062

Title : WZ SGE IN OUTBURST TEN YEARS EARLY: II THE X-RAY EMISSION
PI: Wheatley
Abstract: This is the second half of the WZ Sge DDT proposal. In the first we
requested HRC-S/LETG spectrscopy of the EUV emission. Here we request
ACIS-S observations of the (probably weak) X-ray emission. The X-ray
emission is likely to be supressed below its usual quiescent level
during the outburst, as the emission is thought to switch to the EUV.
However, WZ Sge has never been observed in X-rays during outburst.


Sequence Number: 300055

Title : THE RECURRENT NOVA CI AQL
PI: Greiner
Abstract: Recurrent novae (RN) are expected to emit soft x-rays during a short
interval after the ejected shell has become optically thin and before
the hydrogen shell-burning ceases. Observations of the soft x-rays
will test theoretical models and will also test the conjecture that RN
are SN Ia progenitors. Unfortunatley, no RN occurred during the ROSAT
years, and in fact only one has been detected as a soft X-ray emitter
(Kahabka etal 1999). CI Aql went into outburst in Apr. 2000. Hachisu &
Kato (2001; astro-ph/0104461) predict that CI Aql should have recently
become active at soft X-ray wavelengths and is potentially detectable
until Aug. 2001. We propose (1) a 2 ksec ACIS-S observation to verify
the existence of soft X-rays, and (2) if soft X-rays are discovered, a
20 ksec LETG-HRC observation to determine crucial parameters (white
dwarf mass, effective temperature, composition, luminosity, wind
properties).


Sequence Number: 500202

Title : TOO OBSERVATIONS OF SGR 1900+14 IN AN ACTIVE STATE
PI: Kouveliotou
Abstract: SGR 1900+14 has just emitted a second giant flare (GCN #1041); this is
the second source, which has emitted giant flares (01/04/18 and
98/08/27), in the last 20 years. SGR flares are extremenly rare events
and release over 10^44 ergs. The previous flare, changed the pulse
shape of the neutron star significantly (from four peaks to a single
peak sinusoid) indicating dramatic B-field changes. We have evidence
(yet unpublished) that the pulse shape is changing back to its complex
form. We wish to investigate and understand: 1) whether there is
another pulse shape change associated with the current SGR activity,
2) whether there is a persistent flux change and confirm the
persistent flux-flare energy output relation we have seen previously,
and 3) whether we confirm a line around 6 keV seen during a burst
emitted two days after the SGR 1900+14 August 27, 1998 flare. If this
is a proton cyclotron line, we will for the first time be able to
measure directly the magnetic field of a magnetar


Sequence Number: 500201

Title : TOO OBSERVATIONS OF SGR 1900+14 IN AN ACTIVE STATE
PI: Kouveliotou
Abstract: SGR 1900+14 has just emitted a second giant flare (GCN #1041); this is
the second source, which has emitted giant flares (01/04/18 and
98/08/27), in the last 20 years. SGR flares are extremenly rare events
and release over 10^44 ergs. The previous flare, changed the pulse
shape of the neutron star significantly (from four peaks to a single
peak sinusoid) indicating dramatic B-field changes. We have evidence
(yet unpublished) that the pulse shape is changing back to its complex
form. We wish to investigate and understand: 1) whether there is
another pulse shape change associated with the current SGR activity,
2) whether there is a persistent flux change and confirm the
persistent flux-flare energy output relation we have seen previously,
and 3) whether we confirm a line around 6 keV seen during a burst
emitted two days after the SGR 1900+14 August 27, 1998 flare. If this
is a proton cyclotron line, we will for the first time be able to
measure directly the magnetic field of a magnetar


Sequence Number: 500198

Title : IMMEDIATE POST-GIANT FLARE OBSERVATIONS OF SGR 1900+14
PI: Kulkarni
Abstract: The Soft Gamma-Ray Repeaters (SGRs) are thought to be magnetars:
isolated neutron stars with dipolar magnetic field strengths in excess
of 1e14 G. The best evidence for this identification are the "giant
flares" of these sources, which are highly super-Eddington and require
the confining pressure and reduced photon cross-section of a strong
B-field. The 27 August 1998 flare of SGR 1900+14 peaked at L_X > 2e43
erg/s and powered a short-lived synchrotron nebula of 8.5 GHz flux >
0.3 mJy at its peak. Chandra ACIS-S observations of SGR 1900+14 in the
near aftermath of its recent flare (GCN 1041) will enable a search for
spectral features in the post-flare X-ray emission, which may exhibit
~1e37 erg/s bursts of its own. Strohmayer & Ibrahim (2000) have
reported a ~6.4 keV line with XTE observations of SGR 1900+14;
detection of this line with ACIS will provide valuable insight into
these objects. Coordinated observations with the VLA/VLBA are
underway, and will be arranged with RXTE.


Sequence Number: 400113

Title : OBSERVATIONS OF A BLACK HOLE CANDIDATE X-RAY TRANSIENT DURING OUTBURST
DECAY
PI: Tomsick
Abstract: We propose to observe the black hole candidate (BHC) X-ray transient
XTE J1550-564 during outburst decay. We have been observing the decay
of the current outburst with RXTE, and, if the source flux continues
its current exponential decay, it will fall below RXTE detection
limits around 2000 July 16. Chandra observations after July 16 will
provide, for the first time, complete coverage of a BHC X-ray
transient decay from outburst to quiescence. Measurements of the flux
and the energy spectrum will address the question of whether there are
major changes in the accretion geometry as the source decays into
quiescence or if the change in X-ray flux is simply due to a drop in
the mass accretion rate. Such information has important implications
for ADAF models, which predict a large change in th


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