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M31CXO2 - M 31 Bulge Chandra X-Ray Point Source Catalog

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Overview

The authors explore the population of X-ray point sources in the bulge of M 31 so as to contrast properties of various subpopulations, such as persistent and transient sources and primordial LMXBs and dynamically formed ones. Based on the data from 26 archival Chandra ACIS observations with aim-points within 10 arcminutes of the center of M 31 (J2000 coordinates of 00:42:44.31, +41:16:09.4), the authors study the source content and properties of various subpopulations of X-ray sources to a maximum distance of 12 arcminutes from the center of M 31.

To a limiting luminosity of ~1035 erg s-1, the authors find 263 X-ray point sources, with ~1/3 of these being background galaxies. A study of the spatial distribution and the luminosity function of the X-ray sources shows that the distribution of primordial LMXBs is consistent with the distribution of the K-band light and that their luminosity function flattens below ~1037 erg s-1 to the dN/dL ~ L-1 law in agreement with the behavior found earlier for LMXBs in the Milky Way and in Cen A. Within a radius of 12 arcminutes, the luminosity function is independent of distance to the center of M 31, in contrast to earlier Chandra studies. The LMXBs located in globular clusters and within ~1 arcminute from the center of M 31 are presumably created via dynamical interactions. The dynamical origin of the r < 1 arcminute sources is strongly suggested by their radial distribution which follows the rho*2 profile rather than the K-band light distribution. Their luminosity function shows a prominent fall-off below log(LX) <~ 36.5. Although the statistics are insufficient to claim a genuine low-luminosity cut-off in the luminosity function, the best fit power-law with a slope of -0.6 +/- 0.2 is significantly flatter than the dN/dL ~ L-1 law. The authors also searched for transients and found 28 sources that varied by a factor larger than 20. Their spatial distribution follows the distribution of the persistent LMXBs within the accuracy allowed by the limited number of transients.


Catalog Bibcode

2007A&A...468...49V

References

A study of the population of LMXBs in the bulge of M31.
    Voss R., Gilfanov M.
   <Astron. Astrophys., 468, 49-59 (2007)>
   =2007A&A...468...49V

Provenance

This HEASARC table was created in March 2010 based on CDS catalog J/A+A/468/49 file table2.dat.

Parameters

Source_Number
A sequential identification number for the X-ray source which uniquely identifies each source in the catalog, in order of increasing angular offset from the center of M 31.

Name
The X-ray source designation using the '[VG2007]' prefix (for Voss and Gilfanov 2007) and the source number, as recommended by the CDS Dictionary of Nomenclature of Celestial Objects.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000 coordinates and to a precision of 0.01 seconds of time in the original table.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000 coordinates and to a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Center_Offset
The angular distance of the X-ray source from the center of M 31 (J2000 coordinates of 00:42:44.31, +41:16:09.4), in arcseconds.

Raw_Counts
The number of counts C in the source region in the energy range 0.5 - 8 keV before correction for PSF, background and confusing sources.

Counts
The X-ray source counts S calculated according to equation (1) of the reference paper, including correction for PSF, background and confusing sources.

Counts_Error
The statistical error in the X-ray source counts S calculated according to equation (2) of the reference paper.

Lx
The X-ray luminosity of the source in the energy range 0.5 - 8 keV, in erg s-1, calculated assuming the source is at the 780 kpc distance of M 31.

Broad_Type
A broad source classification, using the following abbreviations:

    GC    = confirmed globular cluster
    GCC   = globular cluster candidate
    PN    = planetary nebula
    FGS   = foreground star
    Nova  = nova
    Rnova = nova (random match)
    EmO   = emission line object
    RAD   = radio source
    SNR   = supernova remnant
    EXT   = extended source
    t     = transient source
  

Alt_Name_1
A precise source identification and references thereof, using the following abbreviations:

      B68 = Borngen (1968AN....291...19BA), [B68] NN in Simbad
      B90 = Braun (1990ApJS...72..761B), [B90] NNN in Simbad
      Bol = Galleti et al. (2004, Cat. <J/A+A/416/917>), Bol NNN in Simbad
      CFN = Ciardullo et al. (1987ApJ...318..520C, [CFN87] NN in Simbad
      CIA = Ciardullo et al. (1989, Cat. <J/ApJ/339/53>), Ford M 31 NNN
      Cra = Crampton et al. (1984ApJ...284..663C), C84 NNN in Simbad
      Fan = Fan et al. (2005PASP..117.1236F), [FMZ2005] NN in Simbad
      GLG = Gelfand et al. (2004, Cat. <J/ApJS/155/89>), GLG NNN
      MG  = Magnier et al. (1995, Cat. <J/A+AS/114/215>), [MPV95] B-NNN in Simbad
      MLA = Meyssonnier et al. (1993, Cat. <J/A+AS/102/251>), MLA NNNN in Simbad
     Mita = Magnier, 1993, Ph.D. Thesis, MIT
      PIE = Pietsch et al. (2005A&A...442..879P), [PFF2005] WeCAPP-NYYYY-NN
      SI  = Shafter & Irby (2001ApJ...563..749S), [SI2001] 1997-06 in Simbad)
      SIM = Simbad, WSTB 37W135 in Simbad
      W2  = Williams et al. (2004AJ....128.1588W)
  

Alt_Name_2
The source designation in Kong et al. (2002, Cat. J/ApJ/577/738), Williams et al. (2004, Cat. J/ApJ/609/735), and/or Williams et al. (2004AJ....128.1588W).

Source_Flag
Sources not included in Kong et al. (2002, Cat. J/ApJ/577/738), Williams et al. (2004, Cat. J/ApJ/609/735), and/or Williams et al. (2004AJ....128.1588W) are indicated by 'K' if observed in Kaaret (2002, Cat. <J/ApJ/578/114>), else by 'X' to indicate that that these are new sources.

Class
The HEASARC Browse object classification, based on the broad_type parameter value when available.


Contact Person

Questions regarding the M31CXO2 database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 20-Mar-2015