DDT Observations

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.

Cycle	Sequence Number	ObsID	Instrument	Grating	Approved Exposure Time	Actual Exposure Time	Target	Status	Start Time [UT]	Proprietary Time	PI Name

14	702923	15647	ACIS-S	HETG	30.000000	0.000000	Mrk590	unobserved		N	Mathur
14	601099	15648	ACIS-S	NONE	25.000000	0.000000	CXOUJ072648.3+85454	unobserved		N	Roberts
14	401541	15646	ACIS-S	NONE	15.000000	0.000000	NGC404	unobserved		N	Kaaret
14	901095	15625	ACIS-S	NONE	10.000000	9.964770	NuSTARJ163433-47384	observed	Mar 23 2013 8:46AM	D	Tomsick
14	702922	15637	ACIS-S	NONE	15.000000	15.069100	2XMMIJ184725.1-6317	observed	Mar 29 2013 4:28AM	D	Lin
14	401540	15645	HRC-S	NONE	53.000000	53.041959	IGRJ18245-2452	observed	Apr 29 2013 12:24AM	D	Patto
14	502032	15616	ACIS-S	NONE	2.000000	2.064600	M82transient	archived	Feb 24 2013 11:25PM	N	Madej
14	300318	15620	HRC-I	NONE	5.000000	5.179582	M31N2013-01b	archived	Mar 11 2013 11:16PM	N	Henze
14	100097	15631	HRC-I	NONE	5.000000	5.181632	Comet2011L4(PANST	archived	Apr 24 2013 2:21AM	N	Lisse
14	100096	15630	HRC-I	NONE	5.000000	5.189832	Comet2011L4(PANST	archived	Apr 17 2013 11:17AM	N	Lisse
14	100095	15629	ACIS-S	NONE	5.000000	5.071600	Comet2011L4(PANST	archived	Apr 23 2013 11:15PM	N	Lisse
14	100095	15641	ACIS-S	NONE	5.000000	5.183200	Comet2011L4(PANST	archived	Apr 24 2013 12:47AM	N	Lisse
14	100094	15628	ACIS-S	NONE	5.000000	5.074700	Comet2011L4(PANST	archived	Apr 21 2013 1:07PM	N	Lisse
14	100094	15640	ACIS-S	NONE	5.000000	5.180100	Comet2011L4(PANST	archived	Apr 21 2013 2:39PM	N	Lisse
14	100093	15627	ACIS-S	NONE	5.000000	5.070699	Comet2011L4(PANST	archived	Apr 17 2013 8:12AM	N	Lisse
14	100093	15639	ACIS-S	NONE	5.000000	5.177000	Comet2011L4(PANST	archived	Apr 17 2013 9:44AM	N	Lisse
13	702920	15584	ACIS-S	NONE	25.000000	24.966258	Swift-J1644+57	archived	Nov 26 2012 10:25AM	N	Tanvir
13	502021	15268	ACIS-S	NONE	20.000000	20.068815	GRB120804A	archived	Aug 13 2012 11:11AM	N	Troja
13	502020	15265	HRC-I	NONE	10.000000	10.124182	1E2259+586	archived	Aug 21 2012 4:51PM	D	Kas
13	501800	14464	ACIS-S	NONE	10.000000	10.068800	GRB120624B	archived	Jun 30 2012 9:24AM	N	Campana
13	501797	14420	ACIS-S	NONE	20.000000	20.398000	PTF11qcj	archived	Apr 11 2012 8:55AM	N	Corsi
13	501796	14412	ACIS-S	NONE	40.000000	39.641600	SN2011ja	archived	Apr 3 2012 5:10AM	D	Ray
13	501794	14398	ACIS-S	NONE	10.000000	10.062600	PTF11qcj	archived	Feb 26 2012 9:15AM	N	Corsi
13	501793	14382	ACIS-S	NONE	10.000000	9.961085	PTF11qcj	archived	Jan 13 2012 1:43AM	N	Corsi
13	501792	14360	ACIS-S	NONE	20.000000	21.010349	CXOUJ164710.2-45521	archived	Oct 23 2011 3:56PM	D	Israel
13	401435	14442	ACIS-S	NONE	20.000000	20.065073	NGC4088ULX1	archived	Jun 2 2012 3:30AM	D	Mezcua
13	401434	14441	ACIS-S	HETG	20.000000	19.073250	4U1630-47	archived	Jun 3 2012 10:28PM	D	Neilsen
13	401430	14428	ACIS-S	HETG	20.000000	20.103500	SwiftJ1753.5-0127	archived	May 3 2012 3:25PM	D	Soleri
13	401429	14425	ACIS-S	HETG	30.000000	30.088300	MAXIJ1305-704	archived	Apr 29 2012 7:20PM	D	Miller
13	401427	14376	ACIS-S	NONE	2.000000	2.010400	NGC891ULX1	archived	Dec 20 2011 7:12AM	N	Hodges-Kluck
13	300317	15596	HRC-S	LETG	25.000000	25.119933	NovaMon2012	archived	Dec 3 2012 8:01PM	N	Orio
13	300316	15495	ACIS-S	HETG	25.000000	25.049135	PNVJ06393874+055352	archived	Sep 12 2012 9:13AM	N	Ness
13	300312	14426	HRC-S	LETG	20.000000	20.189682	NovaLMC2012	archived	Apr 26 2012 10:12PM	N	Drake
13	200910	15597	ACIS-S	NONE	25.000000	25.074440	MLS121106:014420+082	archived	Nov 23 2012 5:02PM	D	Vianello
13	200830	14402	ACIS-S	NONE	20.000000	20.069599	55Cnc	archived	Apr 5 2012 1:03PM	D	Wheatley
13	200829	14401	ACIS-S	NONE	12.000000	11.786399	55Cnc	archived	Mar 7 2012 2:11AM	D	Wheatley
12	702582	13423	HRC-I	NONE	5.000000	5.187525	SwiftJ2058	archived	Jun 22 2011 3:04PM	N	Cenko
12	702581	13418	ACIS-S	NONE	10.000000	10.040058	TDE_PS1_DDT_C12	archived	May 22 2011 11:16PM	N	Gezari
12	702511	13203	ACIS-S	NONE	16.000000	16.046587	ULASJ1120+0641	archived	Feb 4 2011 12:08PM	D	Simpson
12	600982	13212	ACIS-S	NONE	10.000000	10.186400	NGC1589-OT	archived	Jan 16 2011 3:58AM	N	Filippenko
12	501791	14341	ACIS-S	NONE	40.000000	49.715200	PTF11kly	archived	Aug 27 2011 11:00AM	N	Hughes
12	501789	14329	ACIS-S	NONE	15.000000	14.350399	SwiftJ1834.9-0846	archived	Aug 22 2011 3:46PM	N	Kargaltsev
12	501788	14237	ACIS-S	NONE	10.000000	10.043925	GRB110709B	archived	Oct 31 2011 8:15PM	N	Levan
12	501567	13511	HRC-I	NONE	1.000000	1.181953	SwiftJ1822.3-1606	archived	Jul 28 2011 8:21PM	D	Kouveliotou
12	501563	13419	ACIS-S	NONE	5.000000	5.043424	NewPWNCandidate	archived	Jun 2 2011 2:06PM	N	Miller
12	501549	13217	ACIS-S	NONE	15.000000	15.010343	XTEJ1810-197	archived	Feb 9 2011 12:04AM	D	Perna
12	501548	13210	ACIS-S	NONE	5.000000	5.000000	Crab	archived	Oct 15 2011 4:51AM	N	Weisskopf
12	501547	13209	ACIS-S	NONE	5.000000	5.000000	Crab	archived	Sep 15 2011 4:09AM	N	Weisskopf
12	501546	13208	ACIS-S	NONE	5.000000	5.000000	Crab	archived	Aug 15 2011 9:01AM	N	Weisskopf
12	501545	13207	ACIS-S	NONE	5.000000	5.000000	Crab	archived	Apr 12 2011 2:15PM	N	Weisskopf
12	501544	13206	ACIS-S	NONE	5.000000	5.000000	Crab	archived	Mar 15 2011 6:04AM	N	Weisskopf
12	501543	13205	ACIS-S	NONE	5.000000	5.000000	Crab	archived	Feb 16 2011 4:52PM	N	Weisskopf
12	501542	13204	ACIS-S	NONE	5.000000	3.323628	Crab	archived	Jan 15 2011 12:07AM	N	Weisskopf
12	501540	13154	ACIS-S	NONE	10.000000	10.000000	CrabNebula	archived	Apr 28 2011 6:40AM	N	Weisskopf
12	501539	13153	ACIS-S	NONE	10.000000	10.000000	CrabNebula	archived	Apr 21 2011 11:25PM	N	Weisskopf
12	501538	13152	ACIS-S	NONE	10.000000	10.000000	CrabNebula	archived	Apr 16 2011 8:45AM	N	Weisskopf
12	501537	13151	ACIS-S	NONE	10.000000	10.000000	CrabNebula	archived	Apr 14 2011 2:32PM	N	Weisskopf
12	501536	13150	ACIS-S	NONE	10.000000	10.000000	CrabNebula	archived	Apr 13 2011 11:32PM	N	Weisskopf
12	501535	13149	ACIS-S	NONE	15.000000	15.459500	XTEJ1810-197	archived	Oct 25 2010 4:19AM	D	Bernardini
12	501534	13148	ACIS-S	NONE	30.000000	30.009912	SGR0418+5729	archived	Nov 29 2010 6:10AM	N	Rea
12	501533	13147	ACIS-S	NONE	5.000000	5.000000	Crab	archived	Nov 28 2010 11:17AM	N	ferrigno
12	501532	13146	ACIS-S	NONE	5.000000	5.000000	Crab	archived	Oct 28 2010 5:58PM	N	ferrigno
12	401425	14336	ACIS-S	HETG	16.000000	16.345000	IGRJ17498-2921	archived	Aug 30 2011 1:36PM	N	DiSalvo
12	401425	14337	ACIS-S	HETG	14.000000	14.047270	IGRJ17498-2921	archived	Aug 29 2011 2:22PM	N	DiSalvo
12	401300	13420	HRC-I	NONE	1.000000	1.530581	M15X-2	archived	May 30 2011 4:54PM	N	Sivakoff
12	401297	13252	ACIS-S	NONE	40.000000	40.080000	CXOGClbJ174804.8-24	archived	Apr 29 2011 5:30PM	D	Degenaar
12	401295	13237	ACIS-S	NONE	40.000000	40.077250	HESSJ0632+057	archived	Feb 13 2011 9:28PM	D	Torres
12	401293	13225	ACIS-S	NONE	30.000000	30.078000	CXOGClbJ174804.8-24	archived	Feb 17 2011 9:31AM	D	Wijnands
12	401292	13219	ACIS-S	HETG	12.000000	12.000000	CygX-1	archived	Feb 5 2011 6:56AM	N	McClintock
12	401291	13171	ACIS-S	NONE	4.000000	3.755348	J192430.2+510146	archived	Nov 7 2010 7:58AM	D	Liu
12	401290	13170	ACIS-S	NONE	4.000000	3.961600	J194016.3+463251	archived	Nov 7 2010 2:06PM	D	Liu
12	401289	13169	ACIS-S	NONE	3.000000	2.965220	J192607.1+505252	archived	Nov 12 2010 4:16PM	D	Liu
12	401288	13168	ACIS-S	NONE	3.000000	2.962514	J190822.7+385101	archived	Nov 12 2010 7:57PM	D	Liu
12	401287	13167	ACIS-S	NONE	3.000000	2.960000	J191016.9+392951	archived	Nov 7 2010 6:52AM	D	Liu
12	401286	13166	ACIS-S	NONE	3.000000	2.752000	J193239.6+382518	archived	Nov 4 2010 9:49PM	D	Liu
12	401285	13165	ACIS-S	NONE	3.000000	2.758400	J192630.6+413314	archived	Nov 4 2010 10:50PM	D	Liu
12	401284	13164	ACIS-S	NONE	2.000000	2.097700	J194759.9+413111	archived	Nov 14 2010 3:12AM	D	Liu
12	401283	13163	ACIS-S	NONE	2.000000	2.097586	J191438.6+502857	archived	Nov 7 2010 1:05PM	D	Liu
12	401282	13161	ACIS-S	HETG	30.000000	30.074000	EXO1745-248	archived	Oct 24 2010 11:03AM	D	Bhattacharyya
12	200735	13250	ACIS-S	LETG	20.000000	20.075300	TWHya	archived	Apr 13 2011 12:00PM	N	Guenther
11	702317	12087	ACIS-S	NONE	3.000000	3.061700	Q0957+561	archived	Jun 23 2010 11:29PM	N	Goicoechea
11	702316	12086	ACIS-S	NONE	3.000000	3.062981	Q0957+561	archived	Jun 10 2010 10:14AM	N	Goicoechea
11	702315	12085	ACIS-S	NONE	3.000000	3.061700	Q0957+561	archived	May 25 2010 11:08PM	N	Goicoechea
11	702314	12084	ACIS-S	NONE	3.000000	3.182400	Q0957+561	archived	May 15 2010 4:53AM	N	Goicoechea
11	702313	12083	ACIS-S	NONE	3.000000	3.151800	Q0957+561	archived	Apr 27 2010 1:21PM	N	Goicoechea
11	702312	12082	ACIS-S	NONE	3.000000	3.182400	Q0957+561	archived	Apr 13 2010 1:14PM	N	Goicoechea
11	702311	12081	ACIS-S	NONE	3.000000	3.170500	Q0957+561	archived	Mar 29 2010 9:43PM	N	Goicoechea
11	702310	12080	ACIS-S	NONE	3.000000	3.126300	Q0957+561	archived	Mar 15 2010 12:00PM	N	Goicoechea
11	702309	12079	ACIS-S	NONE	3.000000	3.150100	Q0957+561	archived	Mar 3 2010 2:58PM	N	Goicoechea
11	702308	12078	ACIS-S	NONE	3.000000	3.182400	Q0957+561	archived	Feb 18 2010 6:43AM	N	Goicoechea
11	702307	12077	ACIS-S	NONE	3.000000	3.185800	Q0957+561	archived	Feb 1 2010 12:50AM	N	Goicoechea
11	702306	12076	ACIS-S	NONE	3.000000	3.060000	Q0957+561	archived	Jan 17 2010 12:56PM	N	Goicoechea
11	501531	13139	ACIS-S	NONE	5.000000	5.000000	CrabNebula	archived	Sep 28 2010 5:21AM	N	Weisskopf
11	501371	12312	ACIS-S	NONE	30.000000	30.009198	SGR0418+5729	archived	Jul 23 2010 3:16PM	N	Rea
11	501369	12229	ACIS-S	NONE	15.000000	15.037309	GRB100615A	archived	Jun 21 2010 3:52AM	N	Levan
11	501368	12221	ACIS-S	NONE	10.000000	10.065300	XTEJ1810-197	archived	Jun 7 2010 3:29AM	D	Bernardini
11	401281	13122	ACIS-S	NONE	10.000000	10.026400	ESO243-49HLX-1	archived	Sep 6 2010 10:40PM	D	Farrell
11	401145	12314	ACIS-S	HETG	6.000000	6.000000	CygX-1	archived	Jul 24 2010 5:38PM	N	McClintock
11	401144	12313	ACIS-S	HETG	6.000000	6.070000	CygX-1	archived	Jul 22 2010 4:39PM	N	McClintock
11	401141	12235	ACIS-S	HETG	20.000000	20.079600	CirX-1	archived	Jul 4 2010 5:22AM	N	D'A
11	401138	12127	ACIS-S	HETG	25.000000	23.167750	4U1608-52	archived	Mar 15 2010 4:46AM	N	Ozel
11	300283	12203	HRC-S	LETG	5.000000	5.181632	KTEri	archived	Apr 21 2010 11:03AM	N	Drake
11	300277	12102	HRC-S	LETG	25.000000	23.244182	UScorpii	archived	Feb 14 2010 11:56AM	N	Orio
11	300276	12101	HRC-S	LETG	5.000000	5.158825	KTEri	archived	Feb 6 2010 6:43AM	N	Drake
11	300275	12100	HRC-S	LETG	5.000000	5.181375	KTEri	archived	Jan 31 2010 10:43PM	N	Drake
11	300274	12097	HRC-S	LETG	15.000000	15.183582	KTEri	archived	Jan 23 2010 10:01PM	N	Ness
10	701973	10921	ACIS-S	NONE	5.000000	5.046400	2XMMJ130200.1+27465	archived	Jun 27 2009 3:28AM	N	Watson
10	501174	10929	ACIS-I	NONE	20.000000	20.134400	PSRJ1622-49	archived	Jul 10 2009 7:43AM	3	Rea
10	401137	12066	ACIS-S	HETG	9.000000	8.917250	1A0535+262	archived	Dec 28 2009 11:08AM	D	Reynolds
10	401137	12067	ACIS-S	HETG	11.000000	11.081250	1A0535+262	archived	Dec 31 2009 2:19AM	D	Reynolds
10	401125	11803	HRC-I	NONE	10.000000	10.156982	ESO243-49HLX-1	archived	Aug 17 2009 12:41PM	N	Farrell
10	401124	11802	ACIS-S	NONE	5.000000	5.035200	NGC6440X-2	archived	Aug 10 2009 8:26AM	N	Heinke
10	401066	10919	HRC-I	NONE	1.000000	1.175675	ESO243-49HLX-1	archived	Jul 4 2009 2:15PM	N	Farrell
10	401065	10907	ACIS-S	NONE	20.000000	18.448100	GROJ1655-40	archived	Jun 8 2009 2:46AM	N	Gallo
10	200656	12009	ACIS-S	NONE	25.000000	24.473600	V838Mon	archived	Jan 12 2010 8:44AM	N	Kastner
09	900939	12052	ACIS-I	NONE	112.600000	111.875500	ChandraDeepField-S	archived	Jun 15 2010 4:32PM	4	Tananbaum
09	900939	12053	ACIS-I	NONE	75.000000	69.009060	ChandraDeepField-S	archived	Jul 5 2010 3:30AM	4	Tananbaum
09	900939	12054	ACIS-I	NONE	62.000000	61.810778	ChandraDeepField-S	archived	Jul 9 2010 12:02PM	4	Tananbaum
09	900939	12227	ACIS-I	NONE	55.000000	55.043411	ChandraDeepField-S	archived	Jul 14 2010 9:28PM	4	Tananbaum
09	900939	12230	ACIS-I	NONE	38.000000	34.254918	ChandraDeepField-S	archived	Jul 11 2010 4:18AM	4	Tananbaum
09	900939	12231	ACIS-I	NONE	25.000000	25.047959	ChandraDeepField-S	archived	Jul 12 2010 3:49AM	4	Tananbaum
09	900939	12232	ACIS-I	NONE	34.000000	33.329777	ChandraDeepField-S	archived	Jul 18 2010 8:09PM	4	Tananbaum
09	900939	12233	ACIS-I	NONE	35.000000	36.043659	ChandraDeepField-S	archived	Jul 16 2010 10:52AM	4	Tananbaum
09	900939	12234	ACIS-I	NONE	53.000000	49.800438	ChandraDeepField-S	archived	Jul 22 2010 8:13PM	4	Tananbaum
09	900938	12049	ACIS-I	NONE	88.000000	88.088925	ChandraDeepField-S	archived	May 28 2010 7:18PM	4	Tananbaum
09	900938	12050	ACIS-I	NONE	30.000000	30.048259	ChandraDeepField-S	archived	Jun 3 2010 7:03AM	4	Tananbaum
09	900938	12051	ACIS-I	NONE	58.000000	58.044247	ChandraDeepField-S	archived	Jun 10 2010 11:57AM	4	Tananbaum
09	900938	12218	ACIS-I	NONE	89.200000	89.142158	ChandraDeepField-S	archived	Jun 11 2010 10:33AM	4	Tananbaum
09	900938	12219	ACIS-I	NONE	34.200000	34.106014	ChandraDeepField-S	archived	Jun 6 2010 4:49PM	4	Tananbaum
09	900938	12220	ACIS-I	NONE	48.900000	48.768154	ChandraDeepField-S	archived	Jun 18 2010 1:16PM	4	Tananbaum
09	900938	12222	ACIS-I	NONE	31.000000	31.049146	ChandraDeepField-S	archived	Jun 5 2010 3:09AM	4	Tananbaum
09	900938	12223	ACIS-I	NONE	102.000000	102.041441	ChandraDeepField-S	archived	Jun 13 2010 1:21AM	4	Tananbaum
09	900937	12045	ACIS-I	NONE	101.000000	101.037949	ChandraDeepField-S	archived	Mar 28 2010 4:58PM	4	Tananbaum
09	900937	12046	ACIS-I	NONE	79.000000	79.056119	ChandraDeepField-S	archived	Apr 8 2010 8:31AM	4	Tananbaum
09	900937	12047	ACIS-I	NONE	10.300000	10.276459	ChandraDeepField-S	archived	Apr 12 2010 1:47PM	4	Tananbaum
09	900937	12048	ACIS-I	NONE	140.000000	139.932947	ChandraDeepField-S	archived	May 23 2010 7:26AM	4	Tananbaum
09	900937	12129	ACIS-I	NONE	78.200000	78.160096	ChandraDeepField-S	archived	Apr 3 2010 3:40PM	4	Tananbaum
09	900937	12135	ACIS-I	NONE	63.400000	63.357678	ChandraDeepField-S	archived	Apr 6 2010 9:50AM	4	Tananbaum
09	900937	12137	ACIS-I	NONE	94.000000	94.010314	ChandraDeepField-S	archived	Apr 16 2010 9:10AM	4	Tananbaum
09	900937	12138	ACIS-I	NONE	39.000000	39.044418	ChandraDeepField-S	archived	Apr 18 2010 1:16PM	4	Tananbaum
09	900936	12043	ACIS-I	NONE	131.300000	131.294013	ChandraDeepField-S	archived	Mar 18 2010 1:58AM	4	Tananbaum
09	900936	12044	ACIS-I	NONE	100.800000	100.842837	ChandraDeepField-S	archived	Mar 23 2010 11:55AM	4	Tananbaum
09	900936	12055	ACIS-I	NONE	81.800000	81.749978	ChandraDeepField-S	archived	May 15 2010 5:35PM	4	Tananbaum
09	900936	12123	ACIS-I	NONE	25.100000	25.118041	ChandraDeepField-S	archived	Mar 21 2010 8:23AM	4	Tananbaum
09	900936	12128	ACIS-I	NONE	23.100000	23.104259	ChandraDeepField-S	archived	Mar 27 2010 1:28PM	4	Tananbaum
09	900936	12213	ACIS-I	NONE	62.100000	62.098441	ChandraDeepField-S	archived	May 17 2010 2:55PM	4	Tananbaum
09	701771	9814	ACIS-S	NONE	10.000000	9.907200	SDSSJ0952+2143	archived	Feb 5 2008 4:43PM	N	Komossa
09	501152	10573	ACIS-S	NONE	10.000000	10.152500	GRB080307	archived	Sep 22 2008 8:36AM	N	Page
09	501018	9862	ACIS-S	NONE	30.000000	30.147200	SHB080503	archived	May 25 2008 6:28PM	N	Butler
09	501017	9853	ACIS-S	NONE	30.000000	30.175400	SHB080503	archived	May 7 2008 7:35PM	N	Butler
09	501014	9798	ACIS-S	NONE	18.500000	18.544200	SN2007on	archived	Dec 24 2007 11:15AM	D	Roelofs
09	501014	9799	ACIS-S	NONE	21.500000	21.569800	SN2007on	archived	Dec 27 2007 1:35AM	D	Roelofs
09	401051	10574	HRC-I	NONE	5.000000	5.162669	XTEJ1701-407	archived	Aug 26 2008 8:24PM	D	Kaplan
09	401050	10571	HRC-I	NONE	1.000000	1.183875	VPuppis	archived	Sep 1 2008 1:40AM	N	Maccarone
09	400934	9883	ACIS-S	NONE	10.000000	10.198400	XMMUJ005510.7-37385	archived	Jul 8 2008 9:26PM	N	Kong
09	400933	9882	ACIS-S	NONE	30.000000	30.180000	AXJ1754.2-2754	archived	Jul 15 2008 12:30AM	D	Keek
09	400932	9850	HRC-I	NONE	2.000000	2.186069	XTEJ1719-291	archived	Apr 27 2008 6:34PM	D	Sala
09	400931	9805	ACIS-S	NONE	5.000000	5.175000	m81-ot071213	archived	Dec 21 2007 6:54PM	D	Jonker
09	200569	10845	ACIS-S	NONE	40.000000	40.134400	ZCMa	archived	Dec 28 2008 10:48PM	N	Stelzer
09	200568	10826	HRC-I	NONE	5.000000	4.978425	51Peg	archived	Dec 6 2008 12:52PM	N	Schmitt
09	200568	10825	ACIS-S	NONE	5.000000	4.982400	51Peg	archived	Dec 6 2008 11:21AM	N	Schmitt
09	200526	9768	ACIS-I	NONE	30.000000	28.154200	NGC2264field1	archived	Mar 12 2008 6:10PM	N	Micela
09	200526	9769	ACIS-I	NONE	30.000000	30.150559	NGC2264field1	archived	Mar 28 2008 3:02PM	N	Micela
08	900737	8591	ACIS-I	NONE	46.000000	46.034877	ChandraDeepField-S	archived	Sep 20 2007 5:41AM	N	Tananbaum
08	900737	8592	ACIS-I	NONE	88.000000	87.785596	ChandraDeepField-S	archived	Oct 22 2007 12:36PM	N	Tananbaum
08	900737	8593	ACIS-I	NONE	51.000000	50.145559	ChandraDeepField-S	archived	Oct 6 2007 2:22AM	N	Tananbaum
08	900737	8594	ACIS-I	NONE	151.200000	143.272414	ChandraDeepField-S	archived	Nov 1 2007 12:10PM	N	Tananbaum
08	900737	8595	ACIS-I	NONE	118.000000	116.950436	ChandraDeepField-S	archived	Oct 19 2007 2:35PM	N	Tananbaum
08	900737	8596	ACIS-I	NONE	118.000000	116.640477	ChandraDeepField-S	archived	Oct 24 2007 1:46PM	N	Tananbaum
08	900737	8597	ACIS-I	NONE	61.000000	60.068618	ChandraDeepField-S	archived	Oct 17 2007 7:23AM	N	Tananbaum
08	900737	9575	ACIS-I	NONE	112.400000	110.133372	ChandraDeepField-S	archived	Oct 27 2007 6:09AM	N	Tananbaum
08	900737	9578	ACIS-I	NONE	40.000000	39.084800	ChandraDeepField-S	archived	Oct 30 2007 10:53PM	N	Tananbaum
08	900737	9593	ACIS-I	NONE	48.000000	47.045600	ChandraDeepField-S	archived	Sep 22 2007 8:49PM	N	Tananbaum
08	900737	9596	ACIS-I	NONE	115.400000	113.372872	ChandraDeepField-S	archived	Nov 4 2007 4:30AM	N	Tananbaum
08	900737	9718	ACIS-I	NONE	51.000000	50.030737	ChandraDeepField-S	archived	Oct 3 2007 2:12PM	N	Tananbaum
08	701583	8517	ACIS-S	NONE	5.000000	5.153200	M87	archived	Mar 22 2007 4:06AM	N	Harris
08	701582	8516	ACIS-S	NONE	5.000000	5.159200	M87	archived	Mar 19 2007 10:38AM	N	Harris
08	701581	8515	ACIS-S	NONE	5.000000	5.177600	M87	archived	Mar 14 2007 2:43PM	N	Harris
08	701580	8514	ACIS-S	NONE	5.000000	4.929200	M87	archived	Mar 12 2007 11:52AM	N	Harris
08	701579	8513	ACIS-S	NONE	5.000000	5.182800	M87	archived	Feb 24 2007 3:16AM	N	Harris
08	701578	8512	ACIS-S	NONE	5.000000	5.185600	M87	archived	Feb 21 2007 11:58PM	N	Harris
08	701577	8511	ACIS-S	NONE	5.000000	5.185600	M87	archived	Feb 18 2007 10:23PM	N	Harris
08	701576	8510	ACIS-S	NONE	5.000000	5.183600	M87	archived	Feb 15 2007 9:37AM	N	Harris
08	600649	8524	ACIS-S	NONE	30.000000	30.041600	GRB070125	archived	Mar 5 2007 9:49PM	N	Frail
08	501009	9579	ACIS-I	NONE	20.000000	19.709759	SN2007gr	archived	Aug 29 2007 1:52AM	N	Soderberg
08	500822	8518	ACIS-S	NONE	3.000000	3.043200	SN2005kd	archived	Mar 4 2007 2:54PM	N	Pooley
08	500821	8508	HRC-I	NONE	2.000000	2.159931	1RXSJ141256.0+79220	archived	Feb 18 2007 6:05PM	D	Rutledge
08	500820	8506	ACIS-S	NONE	20.000000	20.182000	CXOJ164710.2-455216	archived	Feb 2 2007 7:26PM	N	Woods
08	400928	9584	HRC-I	NONE	2.000000	2.184531	M15	archived	Sep 5 2007 3:23PM	N	Heinke
08	400691	8564	ACIS-I	NONE	11.200000	11.152000	SWIFTJ1756.9-2508	archived	Jul 6 2007 1:44AM	N	DiSalvo
08	400690	8562	ACIS-S	HETG	10.000000	10.152500	SwiftJ195509.6+2614	archived	Jun 14 2007 6:17PM	D	KANBACH
08	400689	8556	HRC-I	NONE	7.000000	7.180382	CirX-1	archived	May 16 2007 9:11PM	D	Jonker
08	400688	8547	HRC-I	NONE	43.000000	43.290108	CirX-1	archived	Apr 21 2007 5:32AM	D	Jonker
08	100071	9755	ACIS-S	NONE	10.000000	10.137600	17P/Holmes	archived	Oct 31 2007 10:31AM	N	Dennerl
08	100071	9762	ACIS-S	NONE	10.000000	10.188800	17P/Holmes	archived	Oct 31 2007 1:26PM	N	Dennerl
08	100071	9763	ACIS-S	NONE	10.000000	10.179200	17P/Holmes	archived	Oct 31 2007 4:21PM	N	Dennerl
07	600607	7373	ACIS-S	NONE	7.000000	7.184000	XMMUJ132218.3-16424	archived	Jul 31 2006 3:41AM	N	Miniutti
07	500817	8480	HRC-I	NONE	1.000000	1.149025	RBS1774(1RXSJ214303	archived	Nov 26 2006 10:15PM	D	Zane
07	500816	8473	ACIS-S	NONE	30.000000	30.124800	SN2006gy	archived	Nov 14 2006 8:57PM	N	Pooley
07	500815	8457	ACIS-S	NONE	10.000000	9.961600	SN2006jc	archived	Nov 4 2006 6:23AM	N	Immler
07	500814	8455	ACIS-S	NONE	15.000000	15.186750	CXOJ164710.2-455216	archived	Oct 28 2006 7:19AM	D	Kas
07	500693	7277	ACIS-S	NONE	15.000000	14.998400	SN2005ke	archived	Feb 19 2006 11:11AM	N	Immler
07	500692	7276	HRC-I	NONE	1.000000	1.112125	IGRJ15359-5750	archived	Mar 28 2006 4:54AM	N	Israel
07	500691	7275	HRC-I	NONE	1.000000	1.122631	IGRJ18048-1544	archived	Mar 28 2006 4:10AM	N	Israel
07	500690	7274	HRC-I	NONE	1.000000	1.097006	IGRJ17513-2011	archived	Mar 28 2006 3:40AM	N	Israel
07	500689	7273	HRC-I	NONE	1.000000	1.095981	IGRJ17488-3253	archived	Mar 28 2006 3:07AM	N	Israel
07	400680	8273	ACIS-I	NONE	21.600000	20.030359	LSI+61303	archived	Oct 25 2006 10:32PM	N	Perez-Torres
07	400561	7335	ACIS-S	NONE	10.000000	9.376000	PSRB1931+24	archived	Jul 20 2006 3:01PM	D	Rea
07	400559	7272	HRC-I	NONE	2.000000	2.135331	SWIFTJ1626.6-5156	archived	Feb 21 2006 6:28AM	N	Homan
07	400558	7269	ACIS-S	NONE	1.000000	1.161600	HD109962	archived	Feb 2 2006 2:14PM	N	Walter
07	300179	7298	HRC-S	LETG	20.000000	20.126132	RSOph	archived	Jun 4 2006 12:25PM	N	Starrfield
07	300178	7297	HRC-S	LETG	10.000000	9.505082	RSOph	archived	Apr 20 2006 5:43PM	N	Starrfield
07	300177	7296	HRC-S	LETG	10.000000	10.152882	RSOph	archived	Mar 24 2006 12:40PM	N	Starrfield
07	300172	7280	ACIS-S	HETG	10.000000	10.075000	RSOph	archived	Feb 26 2006 3:36PM	N	Starrfield
07	200460	8474	ACIS-I	NONE	10.000000	9.753600	L1415EXor	archived	Nov 18 2006 2:41AM	N	Kastner
07	100067	7334	ACIS-S	NONE	4.000000	4.182400	73P/Schwassmann-Wach	archived	May 23 2006 10:34AM	N	Wolk
07	100066	7333	ACIS-S	NONE	4.000000	4.182400	73P/Schwassmann-Wach	archived	May 23 2006 9:19AM	N	Wolk
07	100065	7332	ACIS-S	NONE	4.000000	4.185600	73P/Schwassmann-Wach	archived	May 23 2006 8:03AM	N	Wolk
07	100064	7331	ACIS-S	NONE	4.000000	4.185600	73P-B/Schwassmann-Wa	archived	May 23 2006 6:48AM	N	Wolk
07	100063	7330	ACIS-S	NONE	4.000000	4.105600	73P-B/Schwassmann-Wa	archived	May 23 2006 5:33AM	N	Wolk
06	701180	6278	ACIS-I	NONE	3.500000	3.638000	IGRJ19473+4452	archived	Jul 31 2005 9:32AM	N	Sunyaev
06	701179	6277	ACIS-I	NONE	3.500000	3.759572	IGRJ13091+1137	archived	Jul 25 2005 10:25AM	N	Sunyaev
06	701178	6276	ACIS-I	NONE	3.500000	3.260449	IGRJ12391-1612	archived	Jul 25 2005 11:45AM	N	Sunyaev
06	701177	6275	ACIS-I	NONE	3.500000	3.260799	IGRJ12026-5349	archived	Jun 16 2005 6:10AM	N	Sunyaev
06	701176	6274	ACIS-I	NONE	3.500000	3.676799	IGRJ11085-5100	archived	Jul 1 2005 3:58AM	N	Sunyaev
06	701175	6273	ACIS-I	NONE	3.500000	3.707715	IGRJ10252-6829	archived	Jul 30 2005 9:24AM	N	Sunyaev
06	701174	6272	ACIS-I	NONE	3.500000	3.257599	IGRJ07563-4137	archived	Jun 16 2005 4:46AM	N	Sunyaev
06	701173	6271	ACIS-I	NONE	3.500000	3.459199	IGRJ05007-7047	archived	Jun 16 2005 3:25AM	N	Sunyaev
06	701172	6227	ACIS-S	NONE	10.000000	10.323190	NGC3690	archived	Feb 14 2005 4:53AM	N	Nandra
06	500685	7241	ACIS-S	NONE	50.000000	50.179190	SN2005gj	archived	Dec 11 2005 5:26PM	N	Pooley
06	500603	6284	ACIS-S	NONE	30.000000	29.788040	SN2005bx	archived	Jul 30 2005 11:11AM	N	Filippenko
06	500601	6269	ACIS-S	NONE	20.000000	20.184090	GRB050412	archived	Apr 17 2005 9:43AM	N	Berger
06	500599	6251	HRC-S	NONE	30.000000	27.149430	SGR1806-20	archived	Apr 22 2005 7:03PM	D	Kouveliotou
06	500598	6224	ACIS-I	NONE	20.000000	19.059190	SGR1806-20	archived	Feb 9 2005 7:25AM	1	Fox
06	500597	6207	ACIS-S	NONE	30.000000	29.100500	SGR1806-20	archived	Feb 8 2005 10:54PM	1	Rea
06	400472	6354	ACIS-S	NONE	20.000000	19.043960	GRB050709	archived	Jul 25 2005 9:03PM	N	Frail
06	400470	6298	HRC-I	NONE	5.000000	4.767531	SAXJ1808.4-3658	archived	Jun 20 2005 11:25PM	N	Chakrabarty
06	400469	6297	ACIS-S	HETG	15.000000	14.344000	SAXJ1808.4-3658	archived	Jun 12 2005 2:32AM	N	Galloway
06	400468	6261	ACIS-S	NONE	10.000000	10.180800	J1638-4725	archived	May 4 2005 7:47PM	N	McLaughlin
06	400467	6259	ACIS-S	NONE	5.000000	5.169599	HESSJ1826-148	archived	Apr 13 2005 3:01AM	N	Funk
06	400447	6181	ACIS-S	NONE	15.000000	14.182800	IGRJ00291+5934	archived	Feb 6 2005 1:45PM	N	Jonker
06	400446	6180	ACIS-S	NONE	10.000000	9.894359	IGRJ00291+5934	archived	Jan 14 2005 12:11AM	N	Jonker
06	400445	6179	ACIS-S	NONE	5.000000	5.185200	IGRJ00291+5934	archived	Jan 1 2005 9:24PM	N	Jonker
06	300171	7186	ACIS-S	HETG	50.000000	50.155000	RTCru	archived	Oct 19 2005 10:41AM	N	SOKOLOSKI
06	200372	6375	HRC-I	NONE	5.000000	5.150881	AlphaCentauri	archived	Dec 17 2006 4:58AM	N	Ayres
06	200371	6374	HRC-I	NONE	5.000000	5.157031	AlphaCentauri	archived	May 12 2006 6:31PM	N	Ayres
06	200370	6373	HRC-I	NONE	5.000000	5.187781	AlphaCentauri	archived	Oct 21 2005 2:59AM	N	Ayres
06	200363	6204	ACIS-S	NONE	5.000000	5.136400	V1118Ori	archived	Jan 26 2005 3:24AM	D	Audard
05	800560	6112	ACIS-I	NONE	10.000000	9.510799	MACS1427.2+4407	archived	Feb 12 2005 2:19AM	N	Allen
05	800559	6111	ACIS-I	NONE	50.000000	50.157877	MACS0744.9+3927	archived	Dec 3 2004 9:25PM	N	Allen
05	800558	6110	ACIS-I	NONE	70.000000	64.042810	MACS1311.0-0311	archived	Apr 20 2005 12:23AM	N	Allen
05	800557	6109	ACIS-I	NONE	40.000000	38.046250	MACS1621.6+3810	archived	Dec 11 2004 2:31PM	N	Allen
05	800557	6172	ACIS-I	NONE	30.000000	30.144270	MACS1621.6+3810	archived	Dec 25 2004 10:04PM	N	Allen
05	800556	6108	ACIS-I	NONE	40.000000	40.169750	MACS0329.7-0212	archived	Dec 6 2004 6:18AM	N	Allen
05	800555	6107	ACIS-I	NONE	38.000000	34.332410	MACS1720.3+3536	archived	Nov 22 2005 9:35PM	N	Allen
05	800555	7225	ACIS-I	NONE	2.000000	2.045959	MACS1720.3+3536	archived	Nov 27 2005 3:12AM	N	Allen
05	800554	6106	ACIS-I	NONE	40.000000	35.770890	MACS0159.8-0849	archived	Dec 4 2004 12:14PM	N	Allen
05	800553	6105	ACIS-I	NONE	40.000000	37.770350	MACS0011.7-1523	archived	Jun 28 2005 11:51AM	N	Allen
05	800552	6104	ACIS-I	NONE	10.000000	9.737000	Abell2204	archived	Sep 20 2004 11:42AM	N	Allen
05	800551	6103	ACIS-I	NONE	10.000000	10.406000	PKS0745-191	archived	Sep 24 2004 12:35AM	N	Allen
05	800550	6102	ACIS-I	NONE	10.000000	10.127000	Abell478	archived	Sep 13 2004 5:15PM	N	Allen
05	800549	6101	ACIS-I	NONE	10.000000	10.050190	Abell2029	archived	Dec 17 2004 3:50AM	N	Allen
05	701014	5302	ACIS-S	NONE	30.000000	31.121000	NGC4395	archived	Apr 11 2004 1:28AM	N	Moran
05	701013	5301	ACIS-S	NONE	30.000000	29.730000	NGC4395	archived	Apr 10 2004 3:06AM	N	Moran
05	600412	5360	ACIS-I	NONE	5.000000	5.174000	CXOGCJ174540.0-2900	archived	Aug 28 2004 12:21PM	N	Baganoff
05	500600	6260	ACIS-S	NONE	10.000000	10.140790	GCRTJ1745-3009	archived	May 1 2005 12:47AM	D	Hyman
05	500591	6129	ACIS-I	NONE	20.000000	19.508000	GRB040912	archived	Sep 21 2004 11:18AM	N	Ricker
05	500590	6128	ACIS-I	NONE	20.000000	18.168000	GRB040912	archived	Sep 15 2004 10:24PM	N	Ricker
05	500585	6098	ACIS-I	NONE	5.000000	4.707000	VHEJ1303-63	archived	Sep 25 2004 6:02PM	D	Halpern
05	500508	5365	ACIS-S	NONE	10.000000	10.163000	GRB040812	archived	Aug 22 2004 10:12AM	N	Kouveliotou
05	500507	5364	ACIS-S	NONE	10.000000	10.175000	GRB040812	archived	Aug 17 2004 7:28AM	N	Kouveliotou
05	500506	5314	ACIS-S	NONE	30.000000	30.156000	GRB031203	archived	Apr 18 2004 11:59AM	D	Kouveliotou
05	500505	5306	ACIS-S	NONE	15.000000	14.758000	SN2001em	archived	Apr 4 2004 7:41PM	N	Pooley
05	500504	5305	HRC-S	LETG	35.000000	35.705000	RXJ0720-3125	archived	Feb 27 2004 4:53AM	N	Vink
05	500503	5298	ACIS-S	NONE	25.000000	21.848000	GRB031203	archived	Jan 22 2004 9:34PM	N	Kulkarni
05	400376	5291	ACIS-S	NONE	10.000000	10.137000	PSRJ0737-3039	archived	Jan 18 2004 7:56PM	1	McLaughlin
05	300145	5293	HRC-S	LETG	40.000000	41.953000	MiraAB	archived	Jan 11 2004 2:09PM	D	Karovska
05	300144	5292	HRC-S	LETG	10.000000	10.308000	V4743Sgr	archived	Feb 28 2004 1:31AM	N	Starrfield
05	200298	5308	ACIS-S	NONE	5.000000	4.963000	IRAS05436-0007	archived	Mar 22 2004 12:35AM	N	Kastner
05	200297	5307	ACIS-S	NONE	5.000000	5.561000	IRAS05436-0007	archived	Mar 7 2004 1:41AM	N	Kastner
05	100053	5321	ACIS-S	NONE	3.400000	3.558000	C/2001Q4(NEAT)	archived	May 12 2004 6:50PM	D	Lisse
05	100053	5325	ACIS-S	NONE	3.300000	3.484000	C/2001Q4(NEAT)	archived	May 12 2004 7:55PM	D	Lisse
05	100053	5326	ACIS-S	NONE	3.300000	3.471000	C/2001Q4(NEAT)	archived	May 12 2004 8:58PM	D	Lisse
04	800375	4438	ACIS-S	NONE	30.000000	29.136000	RCS0439.6-2905	archived	Jun 6 2003 6:17AM	D	Bautz
04	500500	5247	HRC-I	NONE	5.000000	4.871000	IGRJ16316-4028	archived	Jan 18 2004 1:07PM	D	Foschini
04	500499	5246	ACIS-S	NONE	25.000000	25.509000	SN2003jd	archived	Nov 10 2003 7:08PM	N	Watson
04	500498	5240	HRC-I	NONE	3.000000	2.884000	XTEJ1810-197	archived	Nov 1 2003 3:26PM	N	Israel
04	500415	4454	HRC-I	NONE	3.000000	2.833000	XTEJ1810-197	archived	Aug 27 2003 10:43PM	N	Gotthelf
04	500413	4449	ACIS-S	NONE	20.000000	18.435000	SN2002ic	archived	Aug 11 2003 9:40PM	D	Hughes
04	500412	4443	ACIS-S	NONE	25.000000	25.125000	SGR1806-20	archived	Aug 3 2003 12:13PM	D	Woods
04	500411	4432	ACIS-S	LETG	100.000000	98.100000	H2650	archived	Mar 29 2003 3:05AM	N	Ricker
04	500410	4425	ACIS-S	NONE	40.000000	40.172000	GRB030226	archived	Feb 27 2003 5:14PM	N	Pedersen
04	500409	4417	ACIS-S	NONE	30.000000	30.415000	SN2003L	archived	Feb 10 2003 3:59AM	N	Kulkarni
04	400324	4439	ACIS-S	HETG	10.000000	9.987000	XTEJ1814-338	archived	Jun 20 2003 2:12AM	D	Chakrabarty
04	400323	4434	ACIS-S	NONE	47.000000	47.051000	IGRJ16358-4726	archived	Apr 21 2003 3:49AM	D	Kouveliotou
04	400322	4426	HRC-S	NONE	3.000000	2.824000	XTEJ1807-294	archived	Mar 10 2003 8:34AM	D	MARKWARDT
04	400321	4424	ACIS-S	NONE	10.000000	10.687000	XTEJ1908+094	archived	May 14 2003 1:51AM	D	Jonker
04	400320	4423	ACIS-S	NONE	5.000000	5.150000	XTEJ1908+094	archived	Apr 19 2003 3:14PM	D	Jonker
04	400319	4422	ACIS-S	NONE	5.000000	5.212000	XTEJ1908+094	archived	Mar 24 2003 12:07AM	D	Jonker
04	400318	4420	ACIS-S	HETG	75.000000	76.220000	GX339-4	archived	Mar 17 2003 8:05PM	D	Miller
04	100052	5311	HRC-I	NONE	5.640000	5.521000	Moon	archived	May 4 2004 4:36AM	N	Drake
04	100052	5312	HRC-I	NONE	5.600000	5.679000	Moon	archived	Jun 2 2004 8:41AM	N	Drake
04	100052	5324	HRC-I	NONE	5.640000	5.772000	Moon	archived	May 4 2004 7:00AM	N	Drake
04	100052	5327	HRC-I	NONE	5.600000	5.638000	Moon	archived	Jun 2 2004 10:58AM	N	Drake
04	100052	5351	HRC-I	NONE	5.600000	5.471000	Moon	archived	Jul 27 2004 11:13PM	N	Drake
04	100052	5352	HRC-I	NONE	4.700000	4.657000	Moon	archived	Jul 28 2004 1:30AM	N	Drake
03	400247	3476	ACIS-S	NONE	5.000000	0.000000	RXJ170930.2-263927	discarded	Apr 21 2002 5:16AM	D	Jonker
03	700612	3419	ACIS-S	NONE	100.000000	97.944000	MGJ0414+0534	archived	Jan 9 2002 12:00AM	D	Chartas
03	600330	4360	ACIS-I	NONE	5.000000	4.969000	M31	archived	Aug 11 2002 6:15PM	N	Primini
03	500408	4409	ACIS-S	NONE	30.000000	30.431000	GRB021004	archived	Nov 25 2002 5:51PM	N	Sako
03	500407	4405	ACIS-S	NONE	10.000000	10.115000	SN2002HI	archived	Dec 10 2002 5:45PM	N	Lewin
03	500406	4404	ACIS-S	NONE	30.000000	30.335000	SN2002HH	archived	Nov 25 2002 8:58AM	N	Lewin
03	500405	4381	ACIS-S	HETG	80.000000	88.130000	GRB021004	archived	Oct 5 2002 8:58AM	N	Harrison
03	500404	4364	ACIS-S	HETG	80.000000	78.122000	GRB020813	archived	Aug 13 2002 11:46PM	N	Ricker
03	500298	3496	ACIS-S	NONE	25.000000	24.188000	SN2001IG	archived	Jun 11 2002 6:20AM	N	Schlegel
03	500297	3495	ACIS-S	NONE	25.000000	23.734000	SN2001IG	archived	May 21 2002 11:53PM	N	Schlegel
03	500296	3494	ACIS-S	NONE	15.000000	14.755000	XRF020427	archived	May 14 2002 3:55AM	N	Fox
03	500295	3493	ACIS-S	NONE	15.000000	13.916000	XRF020427	archived	May 6 2002 5:46AM	N	Fox
03	500294	3477	ACIS-S	NONE	20.000000	20.057000	GRB020321	archived	Mar 31 2002 2:13AM	N	Fox
03	500292	3449	ACIS-S	NONE	3.000000	2.662000	SGR1900+14	archived	Mar 11 2002 11:03AM	D	Woods
03	500291	3441	ACIS-I	NONE	15.000000	14.672000	XRF011130	archived	Feb 20 2002 10:18AM	N	Ricker
03	500287	3437	ACIS-I	NONE	10.000000	10.064000	GRB020127	archived	Feb 11 2002 11:17AM	N	Fox
03	500286	3436	ACIS-I	NONE	10.000000	9.968000	GRB020127	archived	Jan 31 2002 10:37PM	N	Fox
03	400316	4358	ACIS-I	NONE	5.000000	4.979000	TEVJ2032+4130	archived	Aug 11 2002 8:07PM	D	Butt
03	400315	4285	ACIS-S	NONE	5.000000	4.687000	V4641SGR	archived	Aug 5 2002 4:16AM	D	Rupen
03	400270	3724	ACIS-S	HETG	30.000000	26.400000	CYGX-1	archived	Jul 30 2002 5:42PM	N	Feng
03	400268	3672	ACIS-S	NONE	20.000000	18.255000	XTEJ1550-564	archived	Jun 19 2002 9:17AM	D	Corbel
03	400267	3671	ACIS-S	NONE	5.000000	5.538000	1E1740.7-2942	archived	Aug 17 2002 1:24PM	D	Heindl
03	400266	3670	ACIS-S	HETG	10.000000	10.140000	1E1740.7-2942	archived	Jun 13 2002 7:29PM	D	Heindl
03	400265	3661	ACIS-S	LETG	20.000000	17.961000	XTEJ0929-314	archived	May 15 2002 12:43AM	D	Chakrabarty
03	400256	3490	ACIS-S	NONE	7.000000	7.648000	AQLX-1	archived	Sep 3 2002 4:27PM	D	Rutledge
03	400255	3489	ACIS-S	NONE	7.000000	7.858000	AQLX-1	archived	Aug 18 2002 8:19AM	D	Rutledge
03	400254	3488	ACIS-S	NONE	7.000000	7.172000	AQLX-1	archived	Jul 22 2002 9:01PM	D	Rutledge
03	400253	3487	ACIS-S	NONE	7.000000	6.549000	AQLX-1	archived	Jul 5 2002 3:45PM	D	Rutledge
03	400252	3486	ACIS-S	NONE	7.000000	7.151000	AQLX-1	archived	Jun 11 2002 3:50AM	D	Rutledge
03	400251	3485	ACIS-S	NONE	7.000000	7.672000	AQLX-1	archived	May 20 2002 7:41AM	D	Rutledge
03	400250	3484	ACIS-S	NONE	7.000000	7.160000	AQLX-1	archived	May 4 2002 11:04PM	D	Rutledge
03	400249	3483	HRC-S	NONE	3.000000	2.976000	XTEJ1751-305	archived	Apr 10 2002 4:31PM	D	MARKWARDT
03	400248	3481	ACIS-S	NONE	1.000000	1.133000	XTEJ1908+094	archived	Apr 15 2002 5:39AM	N	Rupen
03	400247	3492	ACIS-S	NONE	5.000000	5.231000	RXJ170930.2-263927	archived	Apr 23 2002 9:58PM	D	Jonker
03	400246	3475	ACIS-S	NONE	5.000000	5.965000	RXJ170930.2-263927	archived	Apr 10 2002 5:49PM	D	Jonker
03	400239	3464	ACIS-S	NONE	5.000000	5.147000	RXJ170930.2-263927	archived	Apr 1 2002 12:43AM	D	Jonker
03	400238	3463	ACIS-S	NONE	8.477000	8.477000	RXJ170930.2-263927	archived	Mar 18 2002 11:46AM	D	Jonker
03	400237	3462	ACIS-S	NONE	15.000000	14.210000	RXJ170930.2-263927	archived	Mar 12 2002 1:52PM	D	Jonker
03	400236	3448	ACIS-S	NONE	30.000000	27.457000	XTEJ1550-564	archived	Mar 11 2002 3:16PM	D	Corbel
03	300090	3455	ACIS-S	HETG	35.000000	34.457000	GKPER	archived	Apr 9 2002 3:06PM	D	Mauche
03	300089	3454	ACIS-S	HETG	35.000000	32.102000	GKPER	archived	Mar 27 2002 9:49AM	D	Mauche
03	300087	3434	ACIS-S	NONE	5.000000	5.629000	IMNORMAE	archived	Feb 4 2002 6:01PM	N	Starrfield
03	100038	4410	HRC-I	NONE	1.000000	1.116000	EARTH	archived	Feb 7 2003 1:23AM	D	Gladstone
03	100034	3447	ACIS-S	NONE	12.000000	11.718000	C/2002C1	archived	Apr 15 2002 1:52AM	D	Dennerl
03	100034	3453	ACIS-S	NONE	12.000000	11.964000	C/2002C1	archived	Apr 15 2002 11:15PM	D	Dennerl
03	100032	3412	ACIS-S	NONE	20.000000	20.122000	FXRT011030	archived	Nov 29 2001 11:09AM	D	Harrison
03	100031	3411	ACIS-S	NONE	50.000000	47.209000	FXRT011030	archived	Nov 9 2001 5:44PM	N	Harrison
02	900066	2239	ACIS-I	NONE	132.000000	132.469000	CDFS	archived	Dec 23 2000 5:49PM	N	GIACCONI
02	900066	2312	ACIS-I	NONE	136.000000	125.323000	CDFS	archived	Dec 13 2000 3:47AM	N	GIACCONI
02	900066	2313	ACIS-I	NONE	132.000000	132.115000	CDFS	archived	Dec 21 2000 2:28AM	N	GIACCONI
02	900066	2406	ACIS-I	NONE	31.000000	30.079000	CDFS	archived	Dec 10 2000 11:51PM	N	GIACCONI
02	900066	2409	ACIS-I	NONE	69.000000	69.895000	CDFS	archived	Dec 19 2000 4:12AM	N	GIACCONI
02	800178	2427	ACIS-S	NONE	20.000000	18.094000	PKS0745-191	archived	Jun 16 2001 5:50AM	D	Fabian
02	700608	3395	ACIS-S	NONE	30.000000	28.777000	MGJ0414+0534	archived	Nov 9 2001 8:34AM	D	Chartas
02	700607	3359	ACIS-S	NONE	6.000000	5.760000	SDSSPJ083643+005453	archived	Jan 29 2002 12:02PM	N	Brandt
02	700606	3358	ACIS-S	NONE	8.000000	8.262000	SDSSPJ130608+035626	archived	Jan 29 2002 6:28AM	N	Brandt
02	700605	3357	ACIS-S	NONE	8.000000	8.057000	SDSSPJ103027+052455	archived	Jan 29 2002 9:11AM	N	Brandt
02	700393	2454	ACIS-S	NONE	5.000000	4.500000	CIRCINUSGALAXY	archived	May 2 2001 4:20PM	N	Matt
02	500285	3380	HRC-S	LETG	170.000000	167.446000	RXJ1856.5-3754	archived	Oct 10 2001 5:18AM	N	Tananbaum
02	500285	3381	HRC-S	LETG	170.000000	171.073000	RXJ1856.5-3754	archived	Oct 12 2001 7:31PM	N	Tananbaum
02	500285	3382	HRC-S	LETG	100.500000	101.926000	RXJ1856.5-3754	archived	Oct 8 2001 8:31AM	N	Tananbaum
02	500285	3399	HRC-S	LETG	9.500000	9.318000	RXJ1856.5-3754	archived	Oct 15 2001 11:59AM	N	Tananbaum
02	500200	2459	ACIS-S	NONE	20.000000	18.896000	SGR1900+14	archived	Apr 30 2001 11:27PM	N	Kouveliotou
02	500199	2458	ACIS-S	NONE	20.000000	20.835000	SGR1900+14	archived	Apr 22 2001 4:58AM	N	Kulkarni
02	500197	2424	ACIS-S	NONE	30.000000	29.923000	GRB010222	archived	Feb 22 2001 10:28PM	D	Piro
02	400234	3407	ACIS-S	HETG	30.000000	30.070000	CYGX-1	archived	Oct 28 2001 4:33PM	D	Cui
02	400233	3360	ACIS-S	NONE	2.500000	2.641000	NGC6440	archived	Aug 18 2001 8:23PM	N	in'tZand
02	400164	2430	HRC-I	NONE	10.000000	9.889000	GRS1758-258	archived	Mar 24 2001 7:43AM	D	Heindl
02	400163	2429	ACIS-S	HETG	30.000000	30.280000	GRS1758-258	archived	Mar 24 2001 10:58AM	D	Heindl
02	400162	2428	ACIS-S	NONE	20.000000	20.400000	KS1731-260	archived	Mar 27 2001 12:34AM	D	Wijnands
02	400161	2415	ACIS-S	HETG	30.000000	30.146000	CYGNUSX-1	archived	Jan 4 2001 6:20AM	D	Miller
02	300067	2514	ACIS-S	NONE	10.000000	10.179000	WZSGE	archived	Sep 19 2001 1:56AM	N	Kuulkers
02	300066	2513	ACIS-S	NONE	10.000000	12.075000	WZSGE	archived	Aug 22 2001 8:41AM	N	Kuulkers
02	300065	2512	ACIS-S	NONE	5.000000	4.910000	WZSGE	archived	Aug 7 2001 5:47PM	N	Kuulkers
02	300061	2508	ACIS-S	NONE	5.000000	5.159000	WZSGE	archived	Jul 29 2001 4:49PM	N	Wheatley
02	300059	2506	HRC-S	LETG	20.000000	19.984000	WZSGE	archived	Aug 18 2001 8:07AM	N	Wheatley
02	300058	2505	HRC-S	LETG	20.000000	18.760000	WZSGE	archived	Aug 6 2001 7:53PM	N	Wheatley
02	300057	2504	HRC-S	LETG	20.000000	19.950000	WZSGE	archived	Jul 27 2001 2:44AM	N	Wheatley
02	300056	2492	ACIS-S	NONE	20.000000	19.885000	CIAQL	archived	Aug 1 2001 12:52PM	D	Greiner
02	300054	2465	ACIS-S	NONE	2.000000	2.149000	CIAQL	archived	Jun 1 2001 8:41PM	D	Greiner
02	200125	2338	ACIS-S	HETG	25.000000	24.838000	WR140	archived	May 8 2001 8:01PM	D	Pollock
02	200124	2337	ACIS-S	HETG	50.000000	46.124000	WR140	archived	Dec 29 2000 10:32AM	D	Pollock
01	100011	961	HRC-S	LETG	19.100000	0.000000	Discarded	discarded	Nov 26 1999 9:02AM	3	WAITE
01	700266	1715	HRC-S	LETG	20.000000	19.839000	MRK421	archived	May 29 2000 5:53PM	N	Fruscione
01	700265	1714	ACIS-S	HETG	20.000000	19.830000	MRK421	archived	May 29 2000 11:57AM	N	Fruscione
01	700202	442	ACIS-S	NONE	5.000000	4.976000	NGC526A	archived	Apr 23 2000 6:54AM	S	Wilson
01	570470	1520	ACIS-S	NONE	25.000000	24.035000	NGC3184	archived	Feb 3 2000 11:00AM	3	Schlegel
01	500093	364	HRC-I	NONE	50.000000	48.159000	PSRB0833-45	archived	Feb 21 2000 2:11AM	N	Helfand
01	500092	1518	HRC-I	NONE	50.000000	50.198000	PSRB0833-45	archived	Jan 20 2000 12:33AM	N	Helfand
01	400112	1846	ACIS-S	NONE	5.000000	4.630000	XTEJ1550-564	archived	Sep 11 2000 5:10AM	D	Tomsick
01	400111	1845	ACIS-S	NONE	5.000000	5.164000	XTEJ1550-564	archived	Aug 21 2000 9:08AM	D	Tomsick
01	400110	1701	ACIS-S	LETG	30.000000	27.830000	XTEJ1118+48	archived	Apr 18 2000 6:36PM	D	McClintock
01	400093	426	ACIS-S	HETG	20.000000	18.318000	CYGX-3	archived	Apr 6 2000 8:17PM	N	McCollough
01	400092	425	ACIS-S	HETG	20.000000	21.533000	CYGX-3	archived	Apr 4 2000 2:05PM	N	McCollough
01	300053	2336	ACIS-S	HETG	20.000000	19.222000	ZANDROMEDAE	archived	Nov 13 2000 3:19PM	D	Charles
01	300041	1706	ACIS-S	HETG	60.000000	59.881000	EXHYA	archived	May 18 2000 9:59AM	D	Howell
01	300037	327	ACIS-S	NONE	5.000000	4.947000	Mispointing	archived	Feb 8 2000 4:18PM	D	DiStefano
01	100011	1464	HRC-S	LETG	14.760000	14.778000	JUPITER	archived	Nov 26 1999 2:35PM	3	WAITE
01	100011	1465	HRC-S	LETG	23.150000	23.418000	JUPITER	archived	Nov 26 1999 8:07PM	3	WAITE
01	100010	960	ACIS-S	NONE	22.600000	22.380000	JUPITER	archived	Nov 25 1999 7:38PM	3	WAITE
01	100010	1463	ACIS-S	NONE	22.600000	22.364000	JUPITER	archived	Nov 26 1999 2:10AM	3	WAITE

Canceled DDT Observations
Cycle	Sequence Number	ObsID	Instrument	Grating	Approved Exposure Time	Target	Status	PI Name

13	200829	14409	ACIS-S	NONE	8.000000	55Cnc	canceled	Wheatley
12	401296	13245	HRC-I	NONE	1.000000	MAXIJ1659-152	canceled	Jonker
09	900939	12311	ACIS-I	NONE	18.700000	ChandraDeepField-S	canceled	Tananbaum
09	900936	12214	ACIS-I	NONE	40.000000	ChandraDeepField-S	canceled	Tananbaum
08	900737	9576	ACIS-I	NONE	2.000000	ChandraDeepField-S	canceled	Tananbaum
08	900737	9577	ACIS-I	NONE	30.000000	ChandraDeepField-S	canceled	Tananbaum
07	300182	7301	ACIS-S	HETG	15.000000	RSOph	canceled	Starrfield
07	300181	7300	ACIS-S	HETG	15.000000	RSOph	canceled	Starrfield
07	300180	7299	HRC-S	LETG	20.000000	RSOph	canceled	Starrfield
07	200461	8475	ACIS-I	NONE	10.000000	L1415EXor	canceled	Kastner
06	200365	6206	ACIS-S	NONE	8.333333	V1118Ori	canceled	Audard
06	200364	6205	ACIS-S	NONE	8.333333	V1118Ori	canceled	Audard
04	500414	4450	ACIS-S	NONE	20.000000	SN2002ic	canceled	Hughes
04	100052	5328	HRC-I	NONE	2.500000	Moon	canceled	Drake
04	100052	5313	HRC-I	NONE	4.700000	Moon	canceled	Drake
03	700614	3421	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
03	700613	3420	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
03	500299	3497	ACIS-S	NONE	25.000000	SN2001IG	canceled	Schlegel
03	500290	3440	ACIS-S	NONE	25.000000	SN2002AP	canceled	Schlegel
03	500289	3439	ACIS-S	NONE	25.000000	SN2002AP	canceled	Schlegel
03	500288	3438	ACIS-S	NONE	25.000000	SN2002AP	canceled	Schlegel
03	400269	3723	ACIS-S	NONE	30.000000	MACHO-99-BLG-22	canceled	Reynolds
03	400245	3470	ACIS-S	NONE	10.000000	RXJ170930.2-263927	canceled	Jonker
03	400244	3469	ACIS-S	NONE	10.000000	RXJ170930.2-263927	canceled	Jonker
03	400243	3468	ACIS-S	NONE	10.000000	RXJ170930.2-263927	canceled	Jonker
03	400242	3467	ACIS-S	NONE	5.000000	RXJ170930.2-263927	canceled	Jonker
03	400241	3466	ACIS-S	NONE	5.000000	RXJ170930.2-263927	canceled	Jonker
03	400240	3465	ACIS-S	NONE	5.000000	RXJ170930.2-263927	canceled	Jonker
03	300088	3435	ACIS-S	NONE	25.000000	IMNORMAE	canceled	Starrfield
03	100033	3446	ACIS-S	NONE	8.000000	C/2002C1	canceled	Dennerl
02	700611	3398	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
02	700610	3397	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
02	700609	3396	ACIS-S	NONE	30.000000	MGJ0414+0534	canceled	Chartas
02	500202	2461	ACIS-S	NONE	5.000000	SGR1900+14	canceled	Kouveliotou
02	500201	2460	ACIS-S	NONE	5.000000	SGR1900+14	canceled	Kouveliotou
02	500198	2457	ACIS-S	NONE	0.000000	SGR1900+14	canceled	Kulkarni
02	300064	2511	ACIS-S	NONE	10.000000	WZSGE	canceled	Wheatley
02	300063	2510	ACIS-S	NONE	10.000000	WZSGE	canceled	Wheatley
02	300062	2509	ACIS-S	NONE	10.000000	WZSGE	canceled	Wheatley
02	300055	2466	ACIS-S	NONE	0.000000	CIAQL	canceled	Greiner
01	400113	1847	ACIS-S	NONE	5.000000	XTEJ1550-564	canceled	Tomsick
01	100027	2517	ACIS-S	NONE	9.000000	COMET19P/BORRELLY	canceled	Dennerl
01	100027	3377	ACIS-S	NONE	9.000000	COMET19P/BORRELLY	canceled	Dennerl
01	100027	3378	ACIS-S	NONE	9.000000	COMET19P/BORRELLY	canceled	Dennerl
01	100027	3379	ACIS-S	NONE	9.000000	COMET19P/BORRELLY	canceled	Dennerl

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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).

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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).

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!

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.

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.

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.

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.

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.

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".

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.

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

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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

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.

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).

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.

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.

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.

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.

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.

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).

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).

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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'.

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.

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).

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

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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).

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.

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.

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).

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.

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.

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.

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.

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.

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.

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

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.

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)

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.

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.

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.

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.

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

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).

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.

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.

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.

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).

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.

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

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.

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

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

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

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

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

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

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

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

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.

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

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)

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.

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

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA. Email: cxcweb@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2012. All rights reserved.

List of DDT Observations