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J/ApJ/609/735         M31 Chandra X-ray sources                (Williams+, 2004)

A synoptic X-ray study of M31 with the Chandra high resolution camera. Williams B.F., Garcia M.R., Kong A.K.H., Primini F.A., King A.R., Di Stefano R., Murray S.S. <Astrophys. J., 609, 735-754 (2004)> =2004ApJ...609..735W
ADC_Keywords: Galaxies, nearby ; X-ray sources Keywords: galaxies: individual (M31) - galaxies: spiral - X-rays: binaries - X-rays: galaxies - X-rays: general Abstract: We have obtained 17 epochs of Chandra High Resolution Camera (HRC) snapshot images, each covering most of the M31 disk. The data cover a total baseline of ∼2.5yr and contain a mean effective exposure of 17ks. We have measured the mean fluxes and long-term light curves for 166 objects detected in these data. Description: The data for this project are originally part of a survey program to look for X-ray transients in M31. Nearly every month from 1999 November to 2001 February, Chandra took HRC-I images of five fields covering most of M31. Observations were then made every few months until 2002 June. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 49 81 Summary of Chandra HRC-I observations table2.dat 99 166 Luminosities, variability, other detections, references and object types for the X-ray sources notes.dat 80 31 Notes and references
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/610/247 : M31 supersoft and quasi-soft X-ray sources (Di Stefano+, 2004) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 4 I4 --- ObsID Observation identification number 6- 15 A10 "YYYY/MM/DD" ObsDate Date of observation 17- 18 I2 --- Epoch Observation epoch number 20 I1 h RAh Hour of Right Ascension (J2000) 22- 23 I2 min RAm Minute of Right Ascension (J2000) 25- 29 F5.2 s RAs Second of Right Ascension (J2000) 30 A1 --- DE- Sign of the Declination (J2000) 31- 32 I2 deg DEd Degree of Declination (J2000) 34- 35 I2 arcmin DEm Arcminute of Declination (J2000) 37- 40 F4.1 arcsec DEs Arcsecond of Declination (J2000) 42- 49 F8.3 s ExpTime Exposure time
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 6 A6 --- [KGP2002] Object identification (1) 8 I1 h RAh Hour of Right Ascension (J2000) 10- 11 I2 min RAm Minute of Right Ascension (J2000) 13- 17 F5.2 s RAs Second of Right Ascension (J2000) 18 A1 --- DE- Sign of the Declination (J2000) 19- 20 I2 deg DEd Degree of Declination (J2000) 22- 23 I2 arcmin DEm Arcminute of Declination (J2000) 25- 28 F4.1 arcsec DEs Arcsecond of Declination (J2000) 30- 33 I4 ct Cts Total counts in the detection 35- 39 F5.1 --- S/N Wavdetect measured signal-to-noise 41- 45 F5.1 10+29W Lum Mean luminosity in units of 10^+36^erg/s (2) 47- 49 F3.1 10+29W e_Lum Uncertainty in Lum 51- 57 F7.3 --- chi2 The chi^2^_nu_ of the fit (3) 59- 88 A30 --- CP Counterpart found at other wavelengths or X-ray surveys (4) 90- 92 A3 --- Rem Indicates a note detailed in files notes.dat 94- 98 A5 --- Type Object type (5)
Note (1): Identical sources have the same names in Kong et al. (2002, Cat. J/ApJ/577/738) and Di Stefano et al. (2004, Cat. J/ApJ/610/247). The prefixes are: - r1 designates objects in a square region 2'x2' centered on the nucleus; - r2 designates objects outside of r1 but within a square region 8'x8' centered on the nucleus; - r3 designates objects outside of r2 but within a square region 23'x23' centered on the nucleus; - n1 designates objects outside of r3, north of the nucleus but south of DE=42:01:00 (J2000); - n2 designates objects north of DE=42:01:00 (J2000); - s1 designates objects outside of r3, south of the nucleus but north of DE=40:31:22 (J2000); - s2 designates objects south of DE=40:31:22 (J2000). New objects within these regions are numbered consecutively starting from the highest published number in either Kong et al. (2002, Cat. J/ApJ/577/738) or Di Stefano et al. (2004, Cat. J/ApJ/610/247). The IAU sanctioned names for the sources can be formulated by applying the right ascension and declination to the prefix CXOM31. For example, the proper name of s1-74 is CXOM31 J003956.3+404100. Note (2): Over all epochs. This luminosity was calculated by multiplying the measured flux by the conversion factor discussed in Section 2.3. Note (3): Resulting from a fit of the measured counting rate to a constant source at the mean rate. A value greater than 1.47 indicates that the source has a 90% chance of being variable. Note (4): If the object was detected in previous X-ray surveys as well as in other wavelengths, the optical (or, in one case, radio) counterpart is listed. If the object has no known counterpart outside of the X-ray band, the earliest detection is listed as the X-ray counterpart. With the exception of the "mita" prefix, counterpart names are IAU names taken from the Simbad database (http://simbad.u-strasbg.fr/). X-ray sources with no previous detections and no optical counterparts are labeled "new". Note (5): Flag on [KGP2002], with the following meaning: * = The source has a stellar counterpart. X = The source has no optical counterpart, but a previous X-ray detection is listed. GC = The X-ray source lies in a known M31 globular cluster. SNR = The X-ray source position is coincident with a known M31 supernova remnant. PN = The X-ray source position is coincident with a known, unconfirmed M31 planetary nebula. These may be misidentified SNR. BLL = The X-ray source position is coincident with a BL Lac candidate. Radio = The source has also been detected in the radio. ? = The source has a counterpart of unknown nature.
Byte-by-byte Description of file: notes.dat
Bytes Format Units Label Explanations
1- 3 A3 --- Rem Reference to the note 5- 80 A76 --- Text Note and reference
History: From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 28-Jul-2005
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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