J/ApJ/643/356 Transient X-ray sources in M31 (Williams+, 2006)
A catalog of transient X-ray sources in M31.
Williams B.F., Naik S., Garcia M.R., Callanan P.J.
<Astrophys. J., 643, 356-375 (2006)>
=2006ApJ...643..356W 2006ApJ...643..356W
ADC_Keywords: Galaxies, nearby ; X-ray sources
Keywords: accretion, accretion disks - binaries: close -
galaxies: individual (M31) - X-rays: binaries - X-rays: stars
Abstract:
From 1999 October to 2002 August, 45 transient X-ray sources were
detected in M31 by Chandra and XMM-Newton. We have performed spectral
analysis of all XMM-Newton and Chandra ACIS detections of these
sources, as well as flux measurements of Chandra HRC detections. The
result is absorption-corrected X-ray light curves for these sources
covering this 2.8yr period, along with spectral parameters for
several epochs of the outbursts of most of the transient sources. We
supply a catalog of the locations, outburst dates, peak observed
luminosities, decay time estimates, and spectral properties of the
transient sources, and we discuss similarities with Galactic X-ray
novae. Duty cycle estimates are possible for eight of the transients
and range from 34% to 2%; upper limits to the duty cycles are
estimated for an additional 15 transients and cover a similar range.
We find five transients that have rapid decay times and may be
ultracompact X-ray binaries. Spectra of three of the transients
suggest that they may be faint Galactic foreground sources. If even
one is a foreground source, this suggests a surface density of faint
transient X-ray sources of ≳1deg2.
Description:
We obtained archival Chandra HRC and ACIS data of M31 with sampling
every few months from 1999 October to 2002 August.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 38 45 Transient catalog
table2.dat 160 195 Spectral Fits to Transient Detections
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See also:
B/chandra : The Chandra Archive Log (CXC, 2002)
J/ApJ/577/738 : M31 Chandra X-ray point sources (Kong+, 2002)
J/ApJ/578/114 : Chandra HRC source in M31 (Kaaret, 2002)
J/ApJ/609/735 : M31 Chandra X-ray sources (Williams+, 2004)
J/ApJ/610/247 : M31 supersoft and quasi-soft X-ray sources (Di Stefano+, 2004)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- [KGP2002] Source identification (origin in Kong et al.
2002ApJ...577..738K 2002ApJ...577..738K, Cat. J/ApJ/577/738)
9- 10 I2 h RAh Riight ascension (J2000.0)
12- 13 I2 min RAm Right ascension (J2000.0)
15- 19 F5.2 s RAs Right ascension (J2000.0)
21 A1 --- DE- Declination sign (J2000.0)
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 32 F5.2 arcsec DEs Declination (J2000.0)
34- 38 A5 --- Ref Detection references (1)
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Note (1): References as follows:
1 = Di Stefano et al., 2004ApJ...610..247D 2004ApJ...610..247D, Cat. J/ApJ/610/247
2 = Garcia et al., 2001ATel...79....1G 2001ATel...79....1G
3 = Kong et al., 2001ATel...76....1K 2001ATel...76....1K
4 = Kong et al., 2002ApJ...577..738K 2002ApJ...577..738K, Cat. J/ApJ/577/738
5 = Kong et al., 2002ATel...97....1K 2002ATel...97....1K
6 = New
7 = Osborne et al., 2001A&A...378..800O 2001A&A...378..800O
8 = Shirey, 2001IAUC.7659....1S 2001IAUC.7659....1S
9 = Trinchieri & Fabbiano, 1991ApJ...382...82T 1991ApJ...382...82T
10 = Trudolyubov et al., 2001ApJ...563L.119T 2001ApJ...563L.119T
11 = Trudolyubov et al., 2002IAUC.7798....2T 2002IAUC.7798....2T
12 = Williams et al., 2004ApJ...609..735W 2004ApJ...609..735W, Cat. J/ApJ/609/735
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- [KGP2002] Source identification
8- 17 A10 "DD/MM/YYYY" Obs.Date Date of Observation
19- 24 A6 --- Inst Telescope/Instrument used
26- 35 I10 --- OBSID Observational identification code
37- 41 I5 ct Ct1 ? Net counts in detection (1)
43- 46 I4 ct Ct2 ? XMM MOS1 net counts in detection
48- 51 I4 ct Ct3 ? XMM MOS2 net counts in detection
53- 55 A3 --- Model Model used to fit spectrum (2)
57- 61 F5.2 10-21cm-2 NH ? Hydrogen column density
63- 66 F4.2 10-21cm-2 E_NH ? Upper uncertainty limit in NH
68- 71 F4.2 10-21cm-2 e_NH ? Uncertainty (or lower limit) in NH
73- 75 F3.1 --- Gamma ? Best fit power law slope
77- 79 F3.1 --- E_Gamma ? Upper uncertainty limit in Gamma
81- 83 F3.1 --- e_Gamma ? Uncertainty (or lower limit) in Gamma
85- 89 F5.3 --- T ? Temperature parameter (3)
91- 95 F5.3 --- E_T ? Upper uncertainty limit in T
97-101 F5.3 --- e_T ? Uncertainty (or lower limit) in T
103-109 F7.3 --- chi2 ? Model χ2 value
111-113 I3 --- DoF ? Degrees of freedom
115-119 F5.3 --- Prob ? Probability of fit (4)
121-125 F5.2 --- HR1 ? First hardness ratio, M-S/M+S (5)
127-130 F4.2 --- e_HR1 ? Uncertainty in HR1
132-136 F5.2 --- HR2 ? Second hardness ratio, H-S/H+S (6)
138-141 F4.2 --- e_HR2 ? Uncertainty in HR2
143-148 F6.1 10+29W LX Absorption-corrected X-ray luminosity
in units of 1036 erg/s (7)
150-154 F5.1 10+29W E_LX ? Upper uncertainty limit in LX
156-160 F5.1 10+29W e_LX Uncertainty (or lower limit) in LX
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Note (1): If an XMM observation then this is from the PN instrument.
Note (2): Model used to fit spectrum as follows:
pl = power-law
bb = blackbody
pb = power-law plus blackbody
dbb = disk blackbody
pdb = power-law plus disk blackbody
nsa = neutron star atmosphere
Note (3): For the bb or pb models, this number is kT in keV. For the dbb
model this value is kT in keV of the inner edge of the accretion disk.
For the nsa model this value is log(Teff) for the atmosphere of the
neutron star.
Note (4): The probability that this fit is representative of the true
spectrum, determined from chi/DoF.
Note (5): Calculated by taking the ratio of M-S/M+S, where S is the number
of counts from 0.3-1keV and M is the number of counts from 1-2keV.
Note (6): Calculated by taking the ratio of H-S/H+S, where S is the number
of counts from 0.3-1keV and H is the number of counts from 2-7keV.
Note (7): Assuming a distance of 780kpc.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 26-Sep-2008