Cycle 7 Accepted Large and Very Large Proposals

Title:The Initial Mass Function in the Outer Galaxy: The star forming region NGC 1893

We will explore the effects of environmental conditions, which change dramatically between the inner and outer regions of the Galaxy, on the initial mass function (IMF) of the star forming region NGC 1893. Our proposed 450 ksec observation of NGC 1893, a SFR of ~3 Myr in the outer part of the Galaxy, joint with two hours of Spitzer data, will permit us to identify members down to 0.5 Msun and enable a comparison of NGC 1893's IMF with those derived for SFRs in the solar neighborhood. Our observations will help in determining, particularly in the low mass regime, how the IMF depends on galactic environment. With its spatial resolution and sensitivity, Chandra, with the support of Spitzer, is uniquely suited to achieve our objectives.

Proposal Number	Subject Category	PI Name	Title
07200124	STARS AND WD	Giuseppina Micela	The Initial Mass Function in the Outer Galaxy: The star forming region NGC 1893
07200367	STARS AND WD	Leisa Townsley	Winds, OB Populations, and Young Stars: New Science from M17
07400594	BH AND NS BINARIES	Peter Jonker	The lowest-luminosity quiescent neutron star transient: implications for strong field gravity and the neutron star EoS
07400810	BH AND NS BINARIES	Jon Miller	CHAZSS: The Chandra HETGS Atoll/Z Spectroscopic Survey
07500318	SN, SNR AND ISOLATED NS	Sangwook Park	O-Rich SNR G292.0+1.8: A Textbook Example of a Galactic Core-Collapse SNR
07500764	SN, SNR AND ISOLATED NS	Stephen Reynolds	Kepler's Supernova Remnant: Circumstellar Interactions, Particle Acceleration, and Type Ia Supernova Origins
07610889	NORMAL GALAXIES: DIFFUSE EMISSION	Manami Sasaki	The Chandra ACIS Survey of M33 (ChASeM33): A Deep Survey of the Nearest Face-on Spiral Galaxy
07620395	NORMAL GALAXIES: X-RAY POPULATIONS	Giuseppina Fabbiano	A Chandra legacy program: deep study of LMXB populations
07800432	CLUSTERS OF GALAXIES	David Buote	The Cosmological Formation of Galaxy Groups
07900865	EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS	Luca Zappacosta	Searching for WHIM in Large-Scale Structures
07910613	GALACTIC DIFFUSE EMISSION AND SURVEYS	Michael Muno	A Legacy Study of Stellar Life Cycles at the Galactic Center

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
05:22:50.00	+33:28:05.00	NGC 1893	ACIS-I	NONE	23.0000
05:22:50.00	+33:28:05.00	NGC 1893	ACIS-I	NONE	130.0000
05:22:50.00	+33:28:05.00	NGC 1893	ACIS-I	NONE	160.0000
05:22:50.00	+33:28:05.00	NGC 1893	ACIS-I	NONE	160.0000

We propose to use two ACIS-I pointings centered on the young, massive OB cluster in M17 (the Omega Nebula) and on its powerful X-ray outflow as a testbed for understanding recent and ongoing star formation in the M17 complex and its environmental impact. This rich field is perfect for studying X-ray emission from high-mass as well as intermediate/low-mass stars and for comparing the X-ray luminosity function in a high-mass complex to that in the closer, less powerful Orion Nebula Cluster, recently established by a long Chandra exposure. M17 is ideal for exploring the properties of diffuse X-ray emission to elucidate wind/wind and wind/cloud shock physics in HII regions and for studying embedded stellar clusters and massive protostars forming as M17 interacts with its molecular cloud.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
18:20:29.90	-16:10:44.90	M17 Pointing I	ACIS-I	NONE	40.0000
18:20:29.90	-16:10:44.90	M17 Pointing I	ACIS-I	NONE	160.0000
18:20:29.90	-16:10:44.90	M17 Pointing II	ACIS-I	NONE	35.0000
18:20:29.90	-16:10:44.90	M17 Pointing II	ACIS-I	NONE	65.0000

Title:The lowest-luminosity quiescent neutron star transient: implications for strong field gravity and the neutron star EoS

We propose to obtain a 300 ksec ACIS-S observation of the quiescent neutron star (NS) SXT 1H1905+000. Because of a non-detection during a previous 25 ksec Chandra ACIS-S observation, the NS quiescent luminosity is the lowest of all NS SXTs. It also has a low N_H, a well-known source distance, and an accurately known source position. These observations will eliminate the gap in the derived quiescent luminosities between NS and BH SXTs which is used as being evidence for a BH event horizon. Furthermore, this extremely low NS luminosity allows us to derive that 1H1905+000 harbors a cold, massive NS ruling out all equations of state (EoSs) except the stiffest EoSs for NSs with a nucleonic core. Constraining the NS EoS is one of the ultimate goals of NS studies.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
19:08:27.00	+00:10:08.00	1H 1905+000	ACIS-S	NONE	10.0000
19:08:27.00	+00:10:08.00	1H 1905+000	ACIS-S	NONE	40.0000
19:08:27.00	+00:10:08.00	1H 1905+000	ACIS-S	NONE	42.0000
19:08:27.00	+00:10:08.00	1H 1905+000	ACIS-S	NONE	43.0000
19:08:27.00	+00:10:08.00	1H 1905+000	ACIS-S	NONE	165.0000

High-res. X-ray spectroscopy of accretion-powered sources in the Chandra era has focused on black holes. Neutron stars with low magnetic fields - "Z" and "atoll" binaries - have largely been ignored and/or poorly observed at high resolution. We propose a survey of 6 "Z" and "atoll" neutron star binaries. In a total of only 300 ksec, we can observe each of the 6 sources in our sample twice, obtaining consistent, robust, and constraining spectra free from photon pile-up. High-res. spectroscopy will break degeneracies in X-ray timing-based models for the accretion flows in these systems, and provide new insights into both the origin of the "kHz" QPOs seen in these sources and the nature of the "Z" and "atoll" tracks they trace in color-color diagrams.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
16:40:55.50	-53:45:05.00	4U 1636-53	ACIS-S	HETG	25.0000
16:40:55.50 -53:45:05.00	4U 1636-53	ACIS-S	HETG	25.0000
16:45:47.70	-45:36:40.00	GX 340+0	ACIS-S	HETG	25.0000
16:45:47.70	-45:36:40.00	GX 340+0	ACIS-S	HETG	25.0000
17:02:44.50	-36:25:23.00	GX 349+2	ACIS-S	HETG	25.0000
17:05:44.50	-36:25:23.00	GX 349+2	ACIS-S	HETG	12.5000
17:05:44.50	-36:25:23.00	GX 349+2	ACIS-S	HETG	12.5000
17:38:58.30	-44:27:00.00	4U 1735-44	ACIS-S	HETG	25.0000
17:38:58.30	-44:27:00.00	4U 1735-44	ACIS-S	HETG	25.0000
18:16:01.40	-14:02:11.00	GX 17+2	ACIS-S	HETG	25.0000
18:16:01.40	-14:02:11.00	GX 17+2	ACIS-S	HETG	25.0000
18:23:40.50	-30:21:40.00	4U 1820-30	ACIS-S	HETG	25.0000
18:23:40.50	-30:21:40.00	4U 1820-30	ACIS-S	HETG	25.0000

G292.0+1.8 is the only Galactic supernova remnant (SNR) known to exhibit all the expected characteristics of a core-collapse SNR: stellar ejecta enriched in oxygen, an active pulsar and its wind nebula, and evidence for blast wave interaction with circumstellar material. G292.0+1.8 thus provides an invaluable opportunity for the study of nucleosynthesis and the shock evolution of core-collapse SNRs. We have commenced such a study with our initial Chandra observations of G292.0+1.8. In order to continue the study of this important object, we propose a Chandra Large Project (LP) of G292.0+1.8. The proposed observations will probe the structure of this SNR in unprecedented detail, and will provide an ideal complementary program to the existing Chandra Very Large Project of Cassiopeia A.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
11:24:39.10	-59:16:20.00	G292.0+1.8	ACIS-I	NONE	40.0000
11:24:39.10	-59:16:20.00	G292.0+1.8	ACIS-I	NONE	50.0000
11:24:39.10	-59:16:20.00	G292.0+1.8	ACIS-I	NONE	50.0000
11:24:39.10	-59:16:20.00	G292.0+1.8	ACIS-I	NONE	70.0000
11:24:39.10	-59:16:20.00	G292.0+1.8	ACIS-I	NONE	160.0000
11:24:39.10	-59:16:20.00	G292.0+1.8	ACIS-I	NONE	160.0000

Title:Kepler's Supernova Remnant: Circumstellar Interactions, Particle Acceleration, and Type Ia Supernova Origins

Recent work implies that Kepler's supernova remnant resulted from a Type Ia event, but circumstellar medium (CSM) interaction is also evident. Neither the progenitors nor the detailed explosion mechanisms of SNe Ia are understood, so Kepler offers us a unique opportunity to constrain the progenitor by studying CSM interactions, and the explosion mechanism by studying ejecta. We propose a 750 ks observation, to map the Fe K alpha line on spatial 5" scales, and obtain high-quality spectra in brighter regions on 8" scales. Fe K will map ejecta and discriminate thermal and nonthermal emission at rims. K lines of other alpha elements will show stratification; all should show Doppler broadening to characterize dynamics. A deep observation of Kepler should be a legacy of Chandra.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:30:41.24	-21:29:31.45	Kepler's Supernova R	ACIS-S	NONE	52.0000
17:30:41.24	-21:29:31.45	Kepler's Supernova R	ACIS-S	NONE	1080000
17:30:41.24	-21:29:31.45	Kepler's Supernova R	ACIS-S	NONE	110.0000
17:30:41.24	-21:29:31.45	Kepler's Supernova R	ACIS-S	NONE	160.0000
17:30:41.24	-21:28:60	Kepler's Supernova R	ACIS-S	NONE	160.0000
17:30:41.24	-21:28:60	Kepler's Supernova R	ACIS-S	NONE	160.0000

Title:The Chandra ACIS Survey of M33 (ChASeM33): A Deep Survey of the Nearest Face-on Spiral Galaxy

We propose to study the overall `ecology' of spiral galaxies - the diffuse ISM and the compact sources within - through a survey of M33, the closest face-on spiral. Our ACIS-I survey will cover the central region of M33 with a sensitivity of 5.E34 erg/s for point sources and 1.E35 erg/s for diffuse ones, at least a factor of two deeper than existing XMM data. More importantly, Chandra's superior spatial resolution will give a detailed view of complex structures (superbubbles, supernova remnants, and truly diffuse hot gas) on all scales > 10 pc, will resolve source confusion that confounds previous studies, and will enable identification of most point sources. The rich data set from the M33 survey, together with what promises to be an iconic image, ought to be part of Chandra's legacy.

R.A.	Dec.	Target
01:33:08.87	+30:40:24.92 Field 4	ACIS-I
01:33:08.87	+30:40:24.92
01:33:08.87	+30:40:24.92
01:33:27.90	+30:31:25.30
01:33:27.90	+30:31:25.30
01:33:27.90	+30:31:25.30
01:33:27.90	+30:31:25.30
01:33:33.90	+30:48:40.70
01:33:33.90	+30:48:40.70
01:33:50.80	+30:39:36.60
01:33:50.80	+30:39:36.60
01:34:07.70	+30:30:32.80
01:34:07.70	+30:30:32.80
01:34:07.70	+30:30:32.80
01:34:07.70	+30:30:32.80
01:34:07.70	+30:30:32.80
01:34:07.70	+30:30:32.80
01:34:07.70	+30:30:32.80
01:34:07.70	+30:30:32.80
01:34:13.80	+30:47:48.10
01:34:13.80	+30:47:48.10
01:34:13.80	+30:47:48.10
01:34:33.14	+30:38:44.45
01:34:33.14	+30:38:44.45

NameDet.GratingExp.Time M33 NONE 25.0000 M33 Field 4 ACIS-I NONE 75.0000 M33 Field 4 ACIS-I NONE 100.0000 M33 Field 5 ACIS-I NONE 22.4000 M33 Field 5 ACIS-I NONE 36.2000 M33 Field 5 ACIS-I NONE 41.4000 M33 Field 5 ACIS-I NONE 100.0000 M33 Field 3 ACIS-I NONE 100.0000 M33 Field 3 ACIS-I NONE 100.0000 M33 Field 1 ACIS-I NONE 100.0000 M33 Field 1 ACIS-I NONE 100.0000 M33 Field 6 ACIS-I NONE 12.0000 M33 Field 6 ACIS-I NONE 13.0000 M33 Field 6 ACIS-I NONE 15.0000 M33 Field 6 ACIS-I NONE 15.0000 M33 Field 6 ACIS-I NONE 22.0000 M33 Field 6 ACIS-I NONE 22.0000 M33 Field 6 ACIS-I NONE 23.0000 M33 Field 6 ACIS-I NONE 78.0000 M33 Field 2 ACIS-I NONE 45.0000 M33 Field 2 ACIS-I NONE 55.0000 M33 Field 2 ACIS-I NONE 100.0000 M33 Field 7 ACIS-I NONE 100.0000 M33 Field 7 ACIS-I NONE 100.0000

LMXBs are the only direct fossil evidence of the formation and evolution of binary stars in elliptical galaxies. To understand LMXB formation and evolution, and address the role of globular clusters (GC) in these processes, we propose a 1,245Ks ACIS-S program to study LMXB populations of elliptical galaxies, to limiting luminosities well in the range of normal neutron star binaries. We will study, and compare with models, the spatial distributions and spectral properties of these sources. We will derive, and compare with population synthesis models, their low-luminosity XLFs. Our monitoring approach will constrain the fraction of transients, thus placing important limits on formation mechanisms, binary evolution and disk outburst theory.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	70.0000
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	70.0000
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	85.0000
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	85.0000
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	57.0000
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	57.0000
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	115.0000
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	115.0000
10:47:49.70	+12:34:54.60	NGC3379	ACIS-S	NONE	115.0000

One of the strongest, untested cosmological predictions is the scatter of the concentrations of dark matter halos on the group scale. To quantify this scatter of concentrations requires well-defined samples. We propose a novel systematic study of the core properties of 15 groups representing a complete, X-ray flux-limited sample. In addition to dark matter properties, we will address: (1) entropy and non-gravitational heating, (2) central iron abundances and stellar enrichment, (3) AGN heating and the cooling flow paradox, and (4) the formation of central galaxies. The implications of these measurements for cosmology, supernovae history, star formation and AGN heating will be assessed with numerical simulations. We request observations of 10 unobserved groups in our sample

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time

10:22:04.70	+38:30:43.00	RXC J1022.0+3830	ACIS-S	NONE	42.0000
11:00:48.90	+10:33:35.00	RXC J1100.8+1033	ACIS-S	NONE	27.0000
11:09:43.10	+21:45:43.00	RXC J1109.7+2145	ACIS-S	NONE	37.0000
11:10:32.60	+28:42:59.00	RXC J1110.5+2842	ACIS-S	NONE	27.0000
11:30:01.80	+36:37:49.00	RXC J1130.0+3637	ACIS-S	NONE	50.0000
11:34:50.50	+49:03:28.00	RXC J1134.8+4903	ACIS-S	NONE	52.0000
11:47:20.70	+55:44:36.00	RXC J1147.3+5544	ACIS-S	NONE	44.0000
12:06:37.40	+28:11:01.00	RXC J1206.6+2811	ACIS-S	NONE	36.0000
13:20:15.40	+33:08:30.00	RXC J1320.2+3308	ACIS-S	NONE	39.0000
13:24:11.90	+13:58:45.00	RXC J1324.1+1358	ACIS-S	NONE	21.0000
13:24:11.90	+13:58:45.00	RXC J1324.1+1358	ACIS-S	NONE	26.0000

Simulations and observations indicate that galaxy overdensities are good tracers of the dark matter large-scale structures and therefore of the diffuse warm-hot phase (WHIM) that should be associated with them. The WHIM in these large-scale structures should have large column densities, and therefore should be much easier to detect than the low column density WHIM which has been targeted so far. However, this efficient method of investigating WHIM has yet to be exploited. We have identified 5 bright blazars just in the background of known large-scale structures. We propose to probe and study the WHIM in these structures by identifying the associated absorption lines in the spectrum of these AGNs during their outburst phases, through TOO observations for a total of 300ks with HRC-S/LETG.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time

01:23:08.75	+34:20:49.54	1ES 0120+340	HRC-S	LETG	1.0000
02:32:48.60	+20:17:17.00	1ES 0229+200	HRC-S	LETG	98.0000
16:53:52.20	+39:45:36.60	Mkn 501	HRC-S	LETG	99.0000
22:02:43.30	+42:16:40.00	BL Lac	HRC-S	LETG	1.0000
23:23:52.14	+42:10:58.88	1ES 2321+419	HRC-S	LETG	1.0000

We propose a set of 27 40 ks Chandra observations of the central 300x80 pc of the Galaxy, as part of a multiwavelength project to study stellar life cycles in the region. Our observations will increase the number of accreting compact objects detected there by a factor of 10, to 12,000. This sample will: (1) increase the known number of HMXBs with IR counterparts several-fold, providing stringent tests of population synthesis models, (2) provide spectral and timing data on a new class of faint X-ray transients, (3) identify the sites of recent star formation by detecting their X-ray luminous WR/O stars, (4) identify elusive young pulsars near the Galactic Center, and (5) constrain the physics of particle acceleration in the mysterious radio filaments.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:42:55.00	-29:31:11.30	Deep GCS 13	ACIS-I	NONE	40.0000
17:43:23.70	-29:21:05.00	Deep GCS 10	ACIS-I	NONE	19.0000
17:43:23.70	-29:21:05.00	Deep GCS 10	ACIS-I	NONE	21.0000
17:43:41.50	-29:37:25.70	Deep GCS 12	ACIS-I	NONE	9.9000
17:43:41.50	-29:37:25.70	Deep GCS 12	ACIS-I	NONE	14.7000
17:43:41.50	-29:37:25.70	Deep GCS 12	ACIS-I	NONE	15.4000
17:43:52.20	-29:10:58.10	Deep GCS 7	ACIS-I	NONE	40.0000
17:44:20.70	-29:00:51.10	Deep GCS 4	ACIS-I	NONE	40.0000
17:44:38.60	-29:17:11.40	Deep GCS 6	ACIS-I	NONE	40.0000
17:44:49.10	-28:50:43.40	Deep GCS 1	ACIS-I	NONE	40.0000
17:45:07.10	-29:07:03.70	Deep GCS 3	ACIS-I	NONE	40.0000
17:45:17.40	-28:40:35.80	Deep GCS 26	ACIS-I	NONE	40.0000
17:45:25.10	-29:23:23.60	Deep GCS 8	ACIS-I	NONE	40.0000
17:45:45.60	-28:30:27.40	Deep GCS 24	ACIS-I	NONE	40.0000
17:45:53.50	-29:13:15.20	Deep GCS 5	ACIS-I	NONE	40.0000
17:46:31.80	-28:36:38.20	Deep GCS 23	ACIS-I	NONE	40.0000
17:46:50.00	-28:52:57.40	Deep GCS 27	ACIS-I	NONE	40.0000
17:47:18.10	-28:42:47.90	Deep GCS 25	ACIS-I	NONE	40.0000

The Chandra X-Ray Center (CXC) is operated for NASA by the Smithsonian Astrophysical Observatory. 60 Garden Street, Cambridge, MA 02138 USA. Email: cxchelp@head.cfa.harvard.edu Smithsonian Institution, Copyright © 1998-2026. All rights reserved.