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Detailed Description of J/MNRAS/461/3443 :
M31 deepest Chandra catalogue of point sources (Vulic+, 2016)

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Note : this is the description file of the original catalog. This HTML page corresponds well to the original description, but some minor changes in the format may have been introduced in the FITS output files in order to allow for arithmetic operations on quantities such as coordinates and times. h:m:s and d:m:s units are normally converted into degrees, and YYYY-MM-DD into julian days.
Similarly, some slight changes may have been introduced in the units; the value given in the HTML files supersedes the value indicated in the ReadMe file for this catalogue.
J/MNRAS/461/3443   M31 deepest Chandra catalogue of point sources (Vulic+, 2016)
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X-rays beware: the deepest Chandra catalogue of point sources in M31.
    Vulic N., Gallagher S.C., Barmby P.
   <Mon. Not. R. Astron. Soc., 461, 3443-3456 (2016)>
   =2016MNRAS.461.3443V    (SIMBAD/NED BibCode)
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ADC_Keywords: Galaxy catalogs ; X-ray sources

Keywords: catalogues - galaxies: individual: M31, NGC 224 - X-rays: binaries -
          X-rays: galaxies

Abstract:
    This study represents the most sensitive Chandra X-ray point source
    catalogue of M31. Using 133 publicly available Chandra ACIS-I/S
    observations totalling ~1Ms, we detected 795 X-ray sources in
    the bulge, north-east, and south-west fields of M31, covering an area
    of ~=0.6deg2, to a limiting unabsorbed 0.5-8.0keV luminosity
    of ~1034erg/s. In the inner bulge, where exposure is
    approximately constant, X-ray fluxes represent average values because
    they were determined from many observations over a long period of
    time. Similarly, our catalogue is more complete in the bulge fields
    since monitoring allowed more transient sources to be detected. The
    catalogue was cross-correlated with a previous XMM-Newton catalogue of
    M31's D25 isophote consisting of 1948 X-ray sources, with only 979
    within the field of view of our survey. We found 387 (49 per cent) of
    our Chandra sources (352 or 44 per cent unique sources) matched to
    within 5 arcsec of 352 XMM-Newton sources. Combining this result with
    matching done to previous Chandra X-ray sources we detected 259. new
    sources in our catalogue. We created X-ray luminosity functions (XLFs)
    in the soft (0.5-2.0keV) and hard (2.0-8.0keV) bands that are the
    most sensitive for any large galaxy based on our detection limits.
    Completeness-corrected XLFs show a break around ~=1.3x1037erg/s,
    consistent with previous work. As in past surveys, we find that the
    bulge XLFs are flatter than the disc, indicating a lack of bright
    high-mass X-ray binaries in the disc and an aging population of
    low-mass X-ray binaries in the bulge.

Description:
    We have used 133 publicly available Chandra ACIS-I/S observations
    totalling ~1Ms to create the deepest X-ray point source catalogue
    of M31. We detected 795 X-ray sources within our field of view
    (0.6deg2) to a limiting unabsorbed 0.5-8.0keV luminosity of
    ~1034erg/s. Our 90 per cent (0.3-8.0keV) completeness limit
    is 4x1035erg/s.

File Summary:

FileName Lrecl Records Explanations
× 80 . This file × ReadMe 80 . This file × table3.dat 112 29 ACIS-S observations × table4.dat 112 102 ACIS-I observations × table5.dat 105 795 M31 source list × table6.dat 159 794 Additional M31 source properties × table8.dat 91 795 X-ray catalogue cross-matches
See also: 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 & quasi-soft X-ray sources (Di Stefano+, 2004) J/A+A/468/49 : LMXBs in the bulge of M31 (Voss+, 2007) J/MNRAS/402/803 : M31 globular cluster system (Peacock+, 2010) J/A+A/534/A55 : Deep XMM-Newton Survey of M31 (Stiele+, 2011) J/A+A/555/A65 : X-ray variability of M31 central field (Hofmann+, 2013) J/ApJ/780/83 : X-ray binaries observed in M31 with Chandra (Barnard+, 2014) J/ApJ/802/127 : PHAT stellar cluster survey. II. AP catalog (Johnson+, 2015) Byte-by-byte Description of file: table[34].dat
Bytes Format Units Label Explanations
1- 5 I5 --- ObsID ObsID 7- 16 A10 "date" Date Observation date 18- 25 F8.5 deg RAdeg Right ascension (J2000) (1) 27- 34 F8.5 deg DEdeg Declinatin (J2000) (1) 36- 39 F4.1 arcmin Dist Distance from the centre of M31 (J004244.33+411607.50) 41- 45 I5 ks Livetime Livetime (2) 47- 52 A6 --- Datamode Datamode 54- 59 A6 --- CCDs CCD chips that were on during the observation (3) 61- 65 F5.1 deg RAngle Roll Angle 67- 68 A2 --- Reg Region of the ACIS-S in Fig. 1 (4) 70- 77 F8.5 pix Dx {deltax (5) 79- 86 F8.5 pix Dy {deltay (5) 88- 95 F8.5 deg Rot Rotation (5) 97-103 F7.5 --- Scale Scale Factor (5) 105-106 I2 --- Match Matched Sources (5) 108-112 A5 --- Cat Catalogue (5)
Note (1): pointing of the optical axis, the RA_PNT and DEC_PNT keywords from the level-2 events files. Note (2): Total amount of time that CCDs actually observe a source, which excludes the dead time (e.g. time it takes to transfer charge from the image region to the frame store region). Note (3): CCD chips that were on during the observation, where for ACIS-I we used chips 0123 (I0-I3) for analysis. Also, ObsID's 1581/82 only had 2 active CCDs. Note (4): Region of the ACIS-S as follows: NE = north-east B1 = left (north-east) of the bulge B2 = bulge centre B3 = right (south-west) of the bulge SW = south-west Note (5): These parameters summarize the results from matching each ObsID to a reference astrometric catalogue (see Section 2.2 for details) using the tool wcs_match.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Source sequential number 5- 22 A18 --- CXOU CXOU J name (HHMMSS.ss+DDMMSS.s) 24- 32 F9.6 deg RAdeg Right ascension (J2000) 34- 42 F9.6 deg DEdeg Declination (J2000) 44- 48 F5.2 arcmin Dist Distance from the centre of M31 (J004244.33+411607.50) 50- 52 F3.1 arcsec ePos Positional uncertainty (1) 54- 57 F4.1 arcmin theta Average off-axis angle for merged observations 59- 61 I3 --- Nobs Number of observations extracted 63- 68 A6 --- Det Detector in which the source was detected, ACIS-I, ACIS-S, or Both 70- 71 A2 --- Reg Region for a source detected in ACIS-S or Both 73- 75 I3 ks Texp Total exposure time for merged observations 77- 84 E8.2 s.cm+2 TexpMap Totat exposure map for merged observations 86- 89 F4.1 pix Rsrc Average radius of the source extraction region (in sky pixel = 0.492") 91- 95 F5.1 ---- SNR Photometric significance (net counts / upper error on net counts) (0.3-8.0keV) 97-100 F4.1 keV Emed Background-corrected median photon energy (0.3-8.0keV) 102-105 A4 --- Match Cross-match results from Section 3.4: active galactic nuclei (AGN) or low-mass X-ray binary (LMXB)
Note (1): Positional uncertainty psrt({sigma}x2 + {sigma}y2), where the single-axis position errors {sigma}x and {sigma}y are estimated from the standard deviations of the PSF in the extraction region and the number of counts extracted.
Byte-by-byte Description of file: table6.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Source sequential number 5- 12 E8.4 --- pnsT Poisson probability of a detection not being a source in total band (0.5-8.0keV) 14- 21 E8.4 --- pnsS Poisson probability of a detection not being a source in soft band (0.5-2.0keV) 23- 30 E8.4 --- pnsH Poisson probability of a detection not being a source in hard band (2.0-8.0keV) 32- 40 F9.2 ct NCT Net counts in total band (0.5-8.0keV) 42- 47 F6.2 ct E_NCT Error in NCT (90% upper value) 49- 54 F6.2 ct e_NCT Error in NCT (90% lower value) 56- 63 F8.2 ct NCS Net counts in soft band (0.5-2.0keV) 65- 70 F6.2 ct E_NCS Error in NCS (90% upper value) 72- 77 F6.2 ct e_NCS ?=99.99 Error in NCS (90% lower value) 79- 86 F8.2 ct NCH Net counts in hard band (2.0-8.0keV) 88- 93 F6.2 ct E_NCH Error in NCH (90% upper value) 95-100 F6.2 ct e_NCH ?=99.99 Error in NCH (90% lower value) 102-109 E8.3 mW/m2 FluxT Flux in total band (0.5-8.0keV) (1) 111-119 E9.3 mW/m2 FluxH ?=-9.99 Flux in soft band (0.5-2.0keV) (1) 121-129 E9.3 mW/m2 FluxS ?=-9.99 Flux in hard band (2.0-8.0keV) (1) 131-139 E9.3 mW/m2 FluxTSum Summed flux in total band (0.5-8.0keV) 141-149 E9.3 mW/m2 FluxSSum Summed flux in soft band (0.5-2.0keV) 151-159 E9.3 mW/m2 FluxHSum Summed flux in hard band (2.0-8.0keV)
Note (1): Conversion factors were 5.47, 1.86, and 3.37 in units of 10-9erg/photons for the full, soft, and hard bands (to convert from photon flux in photons/cm2/s to energy flux in erg/cm2/s). The conversion factors account for foreground absorption using an absorbed power-law spectrum with {Gamma}=1.7 and NH=6.66x1020cm-2. To convert energy fluxes to luminosity in erg/s multiply by 7.2x1049((d)/(776kpc))2.cm2. For some sources the soft or hard band had <0 counts, and so uncertainties could not be determined and are represented as -99.99. By extension, some fluxes in the soft or hard band were <0 and so luminosities appear as -9.99. Each source has a pns value <1x10-2 in at least one energy band.
Byte-by-byte Description of file: table8.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Seq Source sequential number 5- 22 A18 --- CXOU CXOU J name (HHMMSS.ss+DDMMSS.s) 24- 27 I4 --- XMMID ?=- XMM identification number 29- 36 A8 --- XMMClass XMM classification 38- 41 A4 --- ChandraCat Chandra catalog (1) 43- 48 A6 --- ChandraID Identification in Chandra catalog 50- 59 A10 --- LMXB1 Peacock et al. (2010, Cat. J/MNRAS/402/803) globular clusters ID 61- 64 I4 --- LMXB2 ?=- Stiele et al. (2011, Cat. J/A+A/534/A55) field ID 66- 69 I4 --- LMXB3 ?=- Stiele et al. (2011, Cat. J/A+A/534/A55) globular clusters ID 71- 74 I4 --- AGN1 ?=- PHAT AGN matching with Andromeda project identification number from Johnson et al., 2015, Cat. J/ApJ/802/127, [JSD2015] AA NNNNN in Simbad 76- 79 A4 --- AGN2 DR12 if AGN in SDSS DR12 81- 84 A4 --- AGN3 NED if AGN in NED 86- 91 A6 --- AGN4 SIMBAD if AGN in Simbad
Note (1): Chandra catalogs as follows: BA = Barnard et al., 2014, Cat. J/ApJ/780/83, [BGP2014] NNN in Simbad DS02 = Di Stefano et al., 2002ApJ...570..618D, [DKG2002] NN in Simbad DS04 = Di Stefano et al., 2004, Cat. J/ApJ/610/247, [KGP2002] AA-NN in Simbad HO = Hofmann et al., 2013, Cat. J/A+A/555/A65, [HPH2013] NNN in Simbad KA = Kaaret, 2002, Cat. J/ApJ/578/114, [K2002] JHHMMSS.ss+DDMMSS.s in Simbad KO = Kong et al., 2002, Cat. J/ApJ/577/738, [KGP2002] rN-NNN in Simbad VO = Voss & Gilfanov, 2007, Cat. J/A+A/468/49, [VG2007] NNN in Simbad WI = Williams et al., 2004, Cat. J/ApJ/609/735
History: From electronic version of the journal ================================================================================ (End) Patricia Vannier [CDS] 08-Dec-2017