M31CFCXO - M 31 Central Field Chandra HRI X-Ray Point Source Catalog
Based on all the available Chandra HRC-I observations (see Table A.1 in the reference paper for the complete list), a source catalog has been created (available in this HEASARC table) and the energy flux of each source in every individual observation derived (these are not available in this HEASARC table, but are obtainable at the CDS: for more details, see the files ftp://cdsarc.u-strasbg.fr/pub/cats/J/A%2BA/555/A65/ReadMe and ftp://cdsarc.u-strasbg.fr/ftp/cats/J_A%2BA/555/A65/table2.dat.gz). One thing to be aware of is that, in the latter file, upper limits are denoted by a '>' symbol rather than the more usual '<' symbol!). These fluxes were calculated assuming a generic power law spectrum and Galactic foreground absorption for each source.
X-ray source variability study of the M 31 central field using Chandra HRC-I. Hofmann F., Pietsch W., Henze M., Haberl F., Strum R., Della Valle M., Hartmann D.H., Hatzidimitriou D. <Astron. Astrophys. 555, A65 (2013)> =2013A&A...555A..65H (SIMBAD/NED BibCode)
A running X-ray source number in order of increasing J2000.0 Right Ascension which uniquely identifies each point source
The name for the Chandra X-ray source based on the '[HPH2013]' prefix (for Hofmann, Pietsch, Henze 2013) and the X-ray source number, created by the HEASARC in anticipation of its recommendation by the CDS Dictionary of Nomenclature of Celestial Objects.
The Right Ascension of the Chandra X-ray source in the selected equinox. This was given in J2000.0 decimal degree coordinates to a precision of 10-5 degrees (0.036 arcseconds) in the original table.
The Declination of the Chandra X-ray source in the selected equinox. This was given in J2000.0 decimal degree coordinates to a precision of 10-5 degrees (0.036 arcseconds) in the original table.
The Galactic Longitude of the Chandra X-ray source.
The Galactic Latitude of the Chandra X-ray source.
The positional uncertainty of the Chandra X-ray source, in arcseconds. This is defined as (presumably the root mean square of) three times the statistical 1-sigma positional error as obtained from wavdetect, not including systematic errors due to centroid offsets at far off-axis positions, and the adopted systematic catalog error from offset correction compared to the 2MASS reference catalog of 0.38 arcseconds (see Section 2.1 of the reference paper for more details).
The net source counts in the source extraction region in the 0.2 - 10 keV bandpass.
The uncertainty in the net source counts in the source extraction region in the 0.2 - 10 keV bandpass.
The estimated background counts in the source extraction region in the 0.2 - 10 keV bandpass.
The source count rate, in ct s-1, in the 0.2 - 10 keV bandpass.
The uncertainty in the source count rate, in ct s-1, in the 0.2 - 10 keV bandpass.
The estimated background count rate within the source extraction region, in ct s-1, in the 0.2 - 10 keV bandpass.
The uncertainty in the estimated background count rate within the source extraction region, in ct s-1, in the 0.2 - 10 keV bandpass.
The exposure time of the most significant detection of the Chandra X-ray source, in seconds.
The highest detection significance of the Chandra X-ray source that was found in any individual observation
The number of the highest resolution image in which the source was detected (see Section 2.1 of the reference paper for more details):
Image # Image Size 0.13" Pixel Binning 1 200" x 200" 1 x 1 2 400" x 400" 2 x 2 3 800" x 800" 4 x 4 4 1400" x 1400" 8 x 8 5 1800" x 1800" 16 x 16 (entire HRC-I)
The energy flux of the Chandra X-ray source in the 0.2 - 10 keV band, in erg s-1 cm-2. This was calculated for a power-law spectrum with a photon index of 1.7 and an assumed Galactic foreground absorption (column density) of NH = 6.6 x 1020 atoms cm-2.
The uncertainty in the energy flux of the Chandra X-ray source in the 0.2 - 10 keV band, in erg s-1 cm-2.
The X-ray luminosity of the Chandra X-ray source, in erg s-1, assuming it is located in M 31 at a distance of 780 kpc and is emitting isotropically..
The uncertainty in the X-ray luminosity of the Chandra X-ray source, in erg s-1.
The angular distance from the Chandra X-ray source to its nearest neighbor, in arcseconds.
The source variability parameter, svar, describing the overall variability of the X-ray source over the 13 years of Chandra observations, and as defined in Section 3.3 and Equation 2 of the reference paper. It is essentially the flux difference between the minimum (or 3-sigma upper limit thereof if that is lower than the lowest detection) and the maximum observed fluxes in terms of standard deviations.
The variability ratio, fvar, which stands for the ratio of the maximum over the minimum flux Fmax/Fmin of the Chandra X-ray source. To calculate these properties, the authors used data points for which the significance of the respective source given by the CIAO tool "aprates" was higher than 1 sigma.
The fractional number, ndet, of > 1-sigma data points in the light curve of the X-ray source with respect to the number of observations in which the source is in the HRC-I detector's FOV.
The maximum value of the source variability parameter, ssvar, defined in the same way as svar except that it describes the overall variability of the X-ray source between any two neighboring observations (see Section 3.3 of the reference paper). The observations have different spacings in time, but the highest variability between them is still a good measure for the variability on time scales from about ten days to one year.
The maximum flux of the Chandra X-ray source in any individual observation, in the 0.2 - 10 keV band, and in units of erg s-1 cm-2.
The uncertainty in the maximum flux of the Chandra X-ray source in any individual observation, in the 0.2 - 10 keV band, and in units of erg s-1 cm-2.
The minimum flux of the Chandra X-ray source in any individual observation, in the 0.2 - 10 keV band, and in units of erg s-1 cm-2.
The uncertainty in the minimum flux of the Chandra X-ray source in any individual observation, in the 0.2 - 10 keV band, and in units of erg s-1 cm-2.
The derived light curve classification of the Chandra X-ray source,as discussed in Section 3.4 of the reference paper, and coded as follows:
HV - highly variable, i.e., ndet > 0.3 and (ssvar > 4 or svar > 5) OB - outburst, i.e., ndet < 0.3 and fvar > 15 and svar > 5
The nova designation of the optical nova associated with the X-ray source, if any, using the nova identifier format: 'M31N YYYY-MMa' for the M31 nova in the year YYYY and month MM, where the appended letter a is used to distinguish multiple novae occurring in the same month.
The globular cluster associated with the X-ray source, if any, and its quality classification. The names and quality flags are taken from the Revised Bologna Catalog of M31 globular clusters and candidates (Galleti et al. 2007, A&A, 471, 127). Thus, 'B055 1' means that the globular cluster's name is B055 and the quality of its identification as a globular cluster is 1, which means it is considered to be a confirmed globular cluster. The other values for this flag for globular clusters herein are 3 ('controversial object') and 6 ('confirmed star(s)').
The source type, based on the identifications in the X-ray, radio, and optical wavelengths, as described in Sect. 3.2 of the reference paper and using the criteria listed in Table 5 therein and summarized below:
Class Meaning and Criteria XRB -X-ray binary: hard X-ray source, HV or OB lightcurve GlC -correlation with optically confirmed globular cluster, hard spectrum SSS -supersoft source: X-rays mostly below 1 keV nova -correlation with optical nova SNR -supernova remnant: softer X-ray source and/or extent, correlation with radio or optical SNR AGN -active galactic nucleus: hard X-rays, radio identifications fgStar -foreground star: softer X-rays, optical identification unclassified
This flag parameter is set to '?' if the type classification is considered to be tentative, i.e., the object is a candidate member of the specified class: in the authors' terminology, such objects are considered to be 'classified' and means that the source has only been a candidate in previous studies or the classification has been obtained only from the variability analysis. If a classification is given and the broad_type_flag is ' ', then the source is regarded as 'identified', meaning that it has been clearly identified in previous studies and this identification is compatible with the HRC-I analysis.
Comments and references on the source, using the following codes:
Code Author(s) ADS Bibcode TPC2006 = Trudolyubov et al., 2006ApJ...645..277T HHP2009 = Haberl et al., 2009ATel.2262....1H GGS2007 = Galache et al., 2007ATel.1171....1G HPG2006 = Haberl et al., 2006ATel..881....1H BGG2012 = Barnard et al., 2012ApJ...756...32B B90 = Braun, 1990ApJS...72..761B HPH2010 = Henze et al., 2010A&A...523A..89H GGT2009 = Galache et al., 2009ATel.1978....1G KGG2009 = Kong et al., 2009ATel.2074....1K HHP2012 = Kong et al., 2012ATel.4164....1H HPH2012a = Henze et al., 2012ATel.3890....1H HPH2012b = Henze et al., 2012ATel.3921....1H HPH2012c = Henze et al., 2013A&A...549A.120H GGT2008 = Galache et al., 2008ATel.1698....1G TP2008 = Trudolyubov & Priedhorsky, 2008ApJ...676.1218T HPH2009 = Henze et al., 2009ATel.2356....1H KGM2001 = Kong et al., 2001ATel...76....1K PBG2008 = Pietsch et al., 2008ATel.1674....1P HHP2007 = Harbel et al., 2007ATel.1296....1H TBP2001 = Trudolyubov et al., 2001ApJ...563L.119T TBP2002 = Trudolyubov et al., 2002ApJ...581L..27T PFH2008 = Pietsch et al., 2008ATel.1647....1P HPH2009 = Henze et al., 2009A&A...500..769H WGM2005 = Williams et al., 2005ApJ...632.1086W BK2009 = Barnard & Kolb, 2009MNRAS.397L..92B BKO2004 = Barnard et al., 2004A&A...423..147B PHH2012 = Pietsch et al., 2010ATel.3038....1P Abbreviations used in other comments on sources no lc = no light curve available AP = activity period SOB = short outburst rec = recurrent XT[SRCID] = cross-talk with SRCID LOB = long outburst ULX = ultra-luminous X-ray source M31* = nucleus of M 31 radio B90 = correlation with radio source in B90 catalog
Other previous X-ray identifications of the source, using the following codes and the format: 'reference catalog','source number' and 'type of source information taken from reference;':
KGP2002 = Kong et al., 2002, ApJ, 577, 38, Notes Ka2002 = Kaaret, 2002, ApJ, 578, 114, CXOM31 PFH2005 = Pietsch et al., 2005, A&A, 434, 483, Class SHL2001 = Supper et al., 2001, A&A, 373, 63, n_SII SHP97 = Supper et al., 1997, A&A, 317, 328, n_ROSAT SPH2008 = Stiele et al., 2008, A&A, 480, 599, Class SPH2011 = Stiele et al., 2011, A&A, 534, A55, Class VG2007 = Voss & Gilfanov, 2007, A&A, 468, 49, Type WGK2004 = Williams et al., 2004, ApJ, 609, 735, Type WNG2006 = Williams et al., 2006, ApJ, 643, 356, F HPH2011 = Henze et al., 2011, A&A, 533, A52, M31N PHS2007 = Pietsch et al., 2007, A&A, 465, 375, M31N CSC = Evans et al., 2010, ApJS, 189, 37, msid D2002 = Di Stefano et al., 2002, ApJ, 570, 618, opt_ident DKG2004 = Di Stefano et al., 2004, ApJ, 610, 247, category O2006 = Orio, 2006, ApJ, 643, 844, type OBT2001 = Osborne et al., 2001, A&A, 378, 800, Comments SBK2009 = Shaw Greening et al., 2009, A&A, 495, 733, type TF91 = Trinchieri & Fabbiano, 1991, ApJ, 382, 82, INDEX TP2004 = Trudolyubov & Priedhorsky, 2004, ApJ, 616, 821, optical_id TP2006 = Trudolyubov et al., 2006, ApJ, 645, 277, class
The HEASARC Browse object classification based on the broad_type parameter value.