Accepted Cycle 11 Observing Proposals

WD BINARES & CV

Proposal Number	Subject Category	PI Name	Title
11300009	WD BINARIES AND CV	Pietsch	Resolving short supersoft source states of optical novae in the core of M31
11300022	WD BINARIES AND CV	Predehl	Resolving short supersoft source states
11300122	WD BINARIES AND CV	Mukai	The Nature of the Soft Component in the Symbiotic Star CH Cygni
11300491	WD BINARIES AND CV	Kong	Primordial formation of close binaries in globular clusters with low desity cores
11300603	WD BINARIES AND CV	Strohmayer	High Resolution Spectroscopy of RX J0806.3+1527
11300610	WD BINARIES AND CV	Dieball	Deep X-ray observations of the Globular Cluster M15: A complete census of the interacting binary population
11300893	WD BINARIES AND CV	Sivakoff	Binary Formation in the Sparse Galactic Globular Cluster NGC 3021

Subject Category: WD BINARIES AND CV

Proposal Number: 11300009

Title: Resolving short supersoft source states of optical novae in the core of M31

PI Name: Wolfgang Pietsch

We propose to continue the monitoring of the M31 core with 5x18.4ks XMM-Newton EPIC and 5x18.4ks Chandra HRC-I observations equally distributed from Nov 2009 to mid Feb 2010 to determine additional lightcurves for short SSS states of optical novae. SSS states with <100 d duration indicate accreting massive white dwarfs. They are proposed as SNIa progenitors and determining their frequency is very important. We will correlate detected sources with novae from optical monitoring. With a nova rate in the field of ~25/yr and SSS states lasting from weeks to years we will follow light curves of many novae. Durations of the nova SSS state will allow us to constrain envelope and white dwarf masses. We will also monitor time variability of ~200 M31 X-ray sources (mostly XRBs).

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
00:42:44.30	+41:16:09.40	M31	HRC-I	NONE	92

Subject Category: WD BINARIES AND CV

Proposal Number: 11300022

Title: Resolving short supersoft source states

PI Name: Peter Predehl

We propose to extend our monitoring of the M31 core by two 20 ks Chandra HRC-I observations to determine light curves of the short SSS states of optical novae. SSS states with <100 d duration indicate accreting massive white dwarfs. They are proposed as SN-Ia progenitors and determining their frequency is very important. The detected sources will be correlated with optical nova positions from monitoring programs covering the same area. With a nova rate in the field of ~25/yr and SSS states lasting from weeks to years we will simultaneously follow light curves of many novae. The duration of nova SSS states will allow us to constrain envelope and white dwarf masses. At the same time we will monitor time variability of ~200 X-ray sources (mostly XRBs) in the central area of M31.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
00:42:44.30	+41:16:09.40	M31	HRC-I	NONE	37

Subject Category: WD BINARIES AND CV

Proposal Number: 11300122

Title: The Nature of the Soft Component in the Symbiotic Star CH Cygni

PI Name: Koji Mukai

The symbiotic star CH Cyg consists of an M giant and a white dwarf, and displays a two-component X-ray spectrum. The absorbed hard X-ray component is likely due to accretion onto the white dwarf. The unabsorbed soft X-ray component is thought to be either due to colliding winds or due to photoionization of the M giant wind by the hard component. We propose to obtain a high signal-to-noise grating spectrum of CH Cyg to resolve the origin of its soft component. Once we know its origin, we can begin to probe the environment around the white dwarf using the detailed spectral shape of the soft component. We propose this as a slow TOO, to be triggered when we know that CH Cyg is X-ray bright. This is a continuation of a TOO proposal accepted in Cycle 10.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
19:24:33.10	+50:14:29.10	CH Cygni	ACIS-S	HETG	100

Subject Category: WD BINARIES AND CV

Proposal Number: 11300491

Title: Primordial formation of close binaries in globular clusters with low desity cores

PI Name: Albert Kong

The primordial binary population is a key input parameter for any realistic model of dense star cluster dynamics. However, the number of primordial binaries and its direct implications for the formation rate of close binaries remain poorly understood. Theoretical calculations show that cataclysmic variables can be formed directly from primordial binaries in or near the core of low core density globular clusters. We propose to use Chandra/HST to study low density core globular clusters systematically and to test the prediction that low-luminosity X-ray sources can be formed from primordial binaries in the cluster core. This project will complement our successful Chandra/HST program to study the dynamical formation of X-ray sources in high core density globular clusters.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:31:54.90	-67:02:52.30	NGC6362	ACIS-S	NONE	40
18:03:50.60	-00:17:48.90	NGC6535	ACIS-S	NONE	53
16:28:40.10	-35:21:13.00	Terzan 3	ACIS-S	NONE	68

Subject Category: WD BINARIES AND CV

Proposal Number: 11300603

Title: High Resolution Spectroscopy of RX J0806.3+1527

PI Name: Tod Strohmayer

RX J0806.3+1527 (HM Cnc) is a candidate double degenerate binary with possibly the shortest known orbital period. We recently obtained the first high resolution X-ray spectrum of the source with an 80 ksec LETG/HRC-S exposure. This spectrum shows the first emission lines ever detected from the system, with a strong detection of an emission feature centered at 27 Angstrom, and indications of weaker emission lines in the 30 - 50 range. The spectrum does not show strong emission lines of typically abundant elements such as carbon, nitrogen, oxygen, and neon. We propose deeper follow-up observations to confirm the tentative line detections and enable elemental identifications and abundances to constrain the formation and binary evolution history of the source.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
08:06:23.20	+15:27:30.20	RX J0806.3+1527	HRC-S	LETG	200

Subject Category: WD BINARIES AND CV

Proposal Number: 11300610

Title: Deep X-ray observations of the Globular Cluster M15: A complete census of the interacting binary population

PI Name: Andrea Dieball

We propose to carry out deep 100 ksec X-ray observations of the globular cluster (GC) M15 with Chandra. M15 has been extensively observed in the far-ultraviolet (FUV) with HST, yielding one of the deepest FUV surveys of a GC to date. Our deep X-ray observations will allow us to (i) find X-ray counterparts to the FUV white dwarf - main sequence star binaries, thus identifying and confirming the cataclysmic variables amongst them; (ii) detect the X-ray faint interacting binaries in this cluster; (iii) detect X-ray counterparts to the pulsars known in the cluster; (iv) classify all X-ray sources based on their X-ray, FUV, NUV and optical properties; (v) and finally test models for IB formation and evolution and verify the empirical results emerging from previous work on other GCs.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
21:29:58.30	+12:10:01.00	M15	ACIS-S	NONE	100

Subject Category: WD BINARIES AND CV

Proposal Number: 11300893

Title: Binary Formation in the Sparse Galactic Globular Cluster NGC 3021

PI Name: Gregory Sivakoff

Bright X-ray sources in globular clusters, X-ray binaries, cataclysmic variables, active binaries, and millisecond pulsars, are all binary systems or thought to be the products of such systems. Studies of X-ray sources in GCs thus probe binary formation. Most past observations have concentrated on dense GCs; these systems show clear evidence for strong dynamical formation of binaries; however, sparse clusters seem to fall off this pattern. Potential explanantions include, among others, primordial binary formation and a misunderstanding of the dynamical state of some GCs. We propose an 85 ks ACIS-S observation of NGC~3201, the nearest sparse GC unobserved by Chandra to test these explanations. We request 1 orbit of HST to discriminate CVs from ABs, and 1 hour of GBT time to search for MSPs.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
10:17:36.80	-46:24:40.00	NGC 3021	ACIS-S	NONE	85

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 © 1998-2025. All rights reserved.