ACDS V10.0 - Detailed Description of J/ApJS/239/13

ACDS V10.0 - Mon Feb 03 14:59:09 CET 2025

| # Detailed Description of J/ApJS/239/13 : Chandra PHAT X-ray catalog of the M31 disk (Williams+, 2018) |

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/ApJS/239/13    Chandra PHAT X-ray catalog of the M31 disk    (Williams+, 2018)
    ================================================================================
    Comparing Chandra and Hubble in the northern disk of M31.
        Williams B.F., Lazzarini M., Plucinsky P.P., Sasaki M., Antoniou V.,
        Vulic N., Eracleous M., Long K.S., Binder B., Dalcanton J.J., Lewis A.R.,
        Weisz D.R.
       <Astrophys. J. Suppl. Ser., 239, 13-13 (2018)>
       =2018ApJS..239...13W    (SIMBAD/NED BibCode)
    ================================================================================
    ADC_Keywords: Galaxies, nearby; X-ray sources; Cross identifications; Optical

    Keywords: galaxies: individual: M31; stars: massive; X-rays: binaries;
              X-rays: galaxies

    Abstract:
        The X-ray source populations within galaxies are typically difficult
        to identify and classify with X-ray data alone. We are able to break
        through this barrier by combining deep new Chandra ACIS-I observations
        with extensive Hubble Space Telescope (HST) imaging from the
        Panchromatic Hubble Andromeda Treasury of the M31 disk. We detect 373
        X-ray sources down to 0.35-8.0keV flux of 10-15erg/cm-2/s over
        0.4deg2, 170 of which are reported for the first time. We identify
        optical counterpart candidates for 188 of the 373 sources, after using
        the HST data to correct the absolute astrometry of our Chandra imaging
        to 0.1". While 58 of these 188 are associated with point sources
        potentially in M31, over half (107) of the counterpart candidates are
        extended background galaxies, 5 are star clusters, 12 are foreground
        stars, and 6 are supernova remnants. Sources with no clear counterpart
        candidate are most likely to be undetected background galaxies and
        low-mass X-ray binaries in M31. The hardest sources in the 1-8keV band
        tend to be matched to background galaxies. The 58 point sources that
        are not consistent with foreground stars are bright enough that they
        could be high-mass stars in M31; however, all but 8 have optical
        colors inconsistent with single stars, suggesting that many could be
        background galaxies or binary counterparts. For point-like
        counterparts, we examine the star formation history of the surrounding
        stellar populations to look for a young component that could be
        associated with a high-mass X-ray binary. About one-third of the point
        sources are not physically associated with a young population, and are
        therefore more likely to be background galaxies. For the 40 point-like
        counterpart candidates associated with young populations, we find that
        their age distribution has two peaks at 15-20Myr and 40-50Myr. If we
        only consider the 8 counterpart candidates with typical high-mass
        main-sequence optical star colors, their age distribution peaks mimic
        those of the sample of 40. Finally, we find that intrinsic faintness,
        and not extinction, is the main limitation for finding further
        counterpart candidates.

    Description:
        In 2015 October, we observed the Panchromatic Hubble Andromeda
        Treasury (PHAT) footprint with Chandra with 7 pointings. The
        footprints are overlaid on a GALEX NUV image of M31, along with the
        corresponding HST coverage, in Figure 1. At each pointing we observed
        for about 50ks in VF mode (Chandra ObsID 17008 to 17014 spanning 2015
        Oct 06 to 2015 Oct 26).

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × table4.dat       751      373   Chandra PHAT X-ray catalog
    × table6.dat       125       57   PHAT point source counterpart candidate
                                     multiwavelength properties
    × table7.dat        47      520   Best high-mass X-ray binary (HMXB) candidate
                                     age probabilities

    See also:
     B/chandra : The Chandra Archive Log (CXC, 1999-2014)
     J/A+A/620/A28 : XMM northern disc of M31 sources (Sasaki+, 2018)
     J/ApJ/846/145 : PHAT. XIX. Formation history of M31 disk (Williams+, 2017)
     J/ApJS/228/2  : Chandra Deep Field-South survey: 7Ms sources (Luo+, 2017)
     J/MNRAS/461/3443 : M31 deepest Chandra catalog of point sources (Vulic+, 2016)
     J/AJ/150/94   : Chandra Local Volume Survey. I. (Binder+, 2015)
     J/ApJ/802/127 : PHAT stellar cluster survey. II. AP catalog (Johnson+, 2015)
     J/other/Ser/189.15 : Point source catalogue of M31. DR2 (Galvin+, 2014)
     J/ApJS/215/9  : PHAT X. UV-IR photometry of M31 stars (Williams+, 2014)
     J/ApJ/786/130 : Catalog of M31 SNR candidates (Lee+, 2014)
     J/ApJ/763/128 : Chandra Local Volume Survey: NGC 404 sources (Binder+, 2013)
     J/ApJ/758/15  : Chandra X-ray point sources of NGC 300 (Binder+, 2012)
     J/A+A/534/A55 : Deep XMM-Newton Survey of M31 (Stiele+, 2011)
     J/ApJS/193/31 : M33 Chandra ACIS survey: final catalog (Tullmann+, 2011)
     J/A+A/495/733 : XMM-Newton spectral survey of M31 disc (Shaw+, 2009)
     J/A+A/451/835 : Properties of X-ray sources in M31/M33 (Hatzidimitriou+, 2006)
     J/A+A/434/483 : An XMM-Newton survey of M 31 (Pietsch+, 2005)
     J/ApJ/610/247 : M31 supersoft and quasi-soft X-ray sources (Di Stefano+, 2004)
     J/ApJ/609/735 : M31 Chandra X-ray sources (Williams+, 2004)
     J/ApJS/150/19 : ChaMP. I. First X-ray source catalog (Kim+, 2004)
     J/ApJ/578/114 : Chandra HRC source in M31 (Kaaret, 2002)
     J/ApJ/577/738 : M31 Chandra X-ray point sources (Kong+, 2002)
     J/A+A/373/63  : M31 second ROSAT PSPC survey (Supper+, 2001)
     J/A+A/317/328 : ROSAT PSPC survey of M 31 (Supper+ 1997)

    Byte-by-byte Description of file:  table4.dat

       Bytes Format Units   Label     Explanations

       1-  3  I3    ---     Seq       Source number in this catalog
       5-  9  I5    ---     ObsID     [17008/17014] Observation in which source
                                        was measured
      11- 28  A18   ---     CXO       Unique source identifier
                                        (HHMMSS.ss+DDMMSS.s; J2000)
      30- 38  F9.6  deg     RAdeg     [10.8/11.8] Right Ascension (J2000)
      40- 48  F9.6  deg     DEdeg     [41.2/42.3] Declination (J2000)
      50- 53  F4.2  arcsec  PosErr    [0.2/5] X-ray position uncertainty
      55- 60  F6.3  arcmin  Theta     [0.4/12.1] Off-axis angle in Chandra
                                        observation
      62- 68  F7.1  ct     C0.35-8.0  [1/15000] Source Net Counts
                                        in 0.35-8.0keV band
      70- 74  F5.1  ct   e_C0.35-8.0  [1/130] Negative uncertainty in C0.35-8.0 (1)
      76- 80  F5.1  ct   E_C0.35-8.0  Positive uncertainty in C0.35-8.0
      82- 89  F8.4  ct     C0.35-1.0  [-2/910] Source Net Counts in 0.35-1.0keV band
      91- 95  F5.2  ct   e_C0.35-1.0  [0.8/99] Negative uncertainty in C0.35-1.0 (1)
      97-100  F4.1  ct   E_C0.35-1.0  Positive uncertainty in C0.35-1.0
     102-108  F7.1  ct      C0.5-8.0  [1/15000] Source Net Counts in 0.5-8.0keV band
     110-114  F5.1  ct    e_C0.5-8.0  [1/120] Negative uncertainty in C0.5-8.0 (1)
     116-120  F5.1  ct    E_C0.5-8.0  Positive uncertainty in C0.5-8.0
     122-129  F8.4  ct      C0.5-1.0  [-2/880] Source Net Counts in 0.5-1.0keV band
     131-135  F5.2  ct    e_C0.5-1.0  [0.8/99] Negative uncertainty in C0.5-1.0 (1)
     137-140  F4.1  ct    E_C0.5-1.0  Positive uncertainty in C0.5-1.0
     142-149  F8.3  ct      C1.0-2.0  [-1/6600] Source Net Counts in 1.0-2.0keV band
     151-155  F5.2  ct    e_C1.0-2.0  [0.8/99] Negative uncertainty in C1.0-2.0 (1)
     157-160  F4.1  ct    E_C1.0-2.0  Positive uncertainty in C1.0-2.0
     162-169  F8.3  ct      C2.0-4.0  [-1/5000] Source Net Counts in 2.0-4.0keV band
     171-175  F5.2  ct    e_C2.0-4.0  [0.8/99] Negative uncertainty in C2.0-4.0 (1)
     177-180  F4.1  ct    E_C2.0-4.0  Positive uncertainty in C2.0-4.0
     182-189  F8.3  ct      C2.0-8.0  [-3/7600] Source Net Counts in 2.0-8.0keV band
     191-195  F5.2  ct    e_C2.0-8.0  [0.8/99] Negative uncertainty in C2.0-8.0 (1)
     197-200  F4.1  ct    E_C2.0-8.0  Positive uncertainty in C2.0-8.0
     202-209  F8.3  ct      C4.0-8.0  [-2/2700] Source Net Counts in 4.0-8.0keV band
     211-215  F5.2  ct    e_C4.0-8.0  [0.8/99] Negative uncertainty in C4.0-8.0 (1)
     217-220  F4.1  ct    E_C4.0-8.0  Positive uncertainty in C4.0-8.0
     222-228  E7.1  ct/s   R0.35-8.0  [4.6e-05/0.3] ARF-corrected Count Rate
                                        in 0.35-8.0keV band
     230-236  E7.1  ct/s e_R0.35-8.0  Negative uncertainty in R0.35-8.0
     238-244  E7.1  ct/s E_R0.35-8.0  Positive uncertainty in R0.35-8.0
     246-253  E8.1  ct/s   R0.35-1.0  ARF-corrected Count Rate in 0.35-2.0 keV band
     255-261  E7.1  ct/s e_R0.35-1.0  [5.3e-05/99] Negative uncertainty
                                       in R0.35-1.0 (1)
     263-269  E7.1  ct/s E_R0.35-1.0  Positive uncertainty in R0.35-1.0
     271-277  E7.1  ct/s    R0.5-8.0  ARF-corrected Count Rate in 0.5-8.0 keV band
     279-285  E7.1  ct/s  e_R0.5-8.0  Negative uncertainty in R0.5-8.0
     287-293  E7.1  ct/s  E_R0.5-8.0  Positive uncertainty in R0.5-8.0
     295-302  E8.1  ct/s    R0.5-1.0  ARF-corrected Count Rate in 0.5-1.0 keV band
     304-310  E7.1  ct/s  e_R0.5-1.0  [4.7e-05/99] Negative uncertainty
                                       in R0.5-1.0 (1)
     312-318  E7.1  ct/s  E_R0.5-1.0  Positive uncertainty in R0.5-1.0
     320-327  E8.1  ct/s    R1.0-2.0  ARF-corrected Count Rate in 1.0-2.0 keV band
     329-335  E7.1  ct/s  e_R1.0-2.0  [1.5e-05/99] Negative uncertainty
                                       in R1.0-2.0 (1)
     337-343  E7.1  ct/s  E_R1.0-2.0  Positive uncertainty in R1.0-2.0
     345-352  E8.1  ct/s    R2.0-4.0  ARF-corrected Count Rate in 2.0-4.0 keV band
     354-360  E7.1  ct/s  e_R2.0-4.0  [1.8e-05/99] Negative uncertainty
                                       in R2.0-4.0 (1)
     362-368  E7.1  ct/s  E_R2.0-4.0  Positive uncertainty in R2.0-4.0
     370-377  E8.1  ct/s    R2.0-8.0  ARF-corrected Count Rate in 2.0-8.0 keV band
     379-385  E7.1  ct/s  e_R2.0-8.0  [2.3e-05/99] Negative uncertainty
                                       in R2.0-8.0 (1)
     387-393  E7.1  ct/s  E_R2.0-8.0  Positive uncertainty in R2.0-8.0
     395-402  E8.1  ct/s    R4.0-8.0  ARF-corrected Count Rate in 4.0-8.0 keV band
     404-410  E7.1  ct/s  e_R4.0-8.0  [1.7e-05/99] Negative uncertainty
                                       in R4.0-8.0 (1)
     412-418  E7.1  ct/s  E_R4.0-8.0  Positive uncertainty in R4.0-8.0
     420-426  E7.1  %       PNS       [0/0.01] Probability no source detected at
                                       this location in 0.35-8.0keV band
     428-434  E7.1  mW/m2  F0.35-8.0  Energy flux in 0.35-8.0 keV band (2)
     436-442  E7.1  mW/m2 e_F0.35-8.0  Negative uncertainty in F0.35-8.0
     444-450  E7.1  mW/m2 E_F0.35-8.0  Positive uncertainty in F0.35-8.0
     452-459  E8.1  mW/m2  F0.35-1.0  Energy flux in 0.35-1.0 keV band (2)
     461-467  E7.1  mW/m2 e_F0.35-1.0  [9.4e-16/99] Negative uncertainty
                                       in F0.35-1.0 (1)
     469-475  E7.1  mW/m2 E_F0.35-1.0  Positive uncertainty in F0.35-1.0
     477-483  E7.1  mW/m2   F0.5-8.0  Energy flux in 0.5-8.0 keV band (2)
     485-491  E7.1  mW/m2 e_F0.5-8.0  Negative uncertainty in F0.5-8.0
     493-499  E7.1  mW/m2 E_F0.5-8.0  Positive uncertainty in F0.5-8.0
     501-508  E8.1  mW/m2   F0.5-1.0  Energy flux in 0.5-1.0 keV band (2)
     510-516  E7.1  mW/m2 e_F0.5-1.0  [6.7e-16/99] Negative uncertainty
                                       in F0.5-1.0 (1)
     518-524  E7.1  mW/m2 E_F0.5-1.0  Positive uncertainty in F0.5-1.0
     526-533  E8.1  mW/m2   F1.0-2.0  Energy flux in 1.0-2.0 keV band (2)
     535-541  E7.1  mW/m2 e_F1.0-2.0  [8.3e-17/99] Negative uncertainty
                                       in F1.0-2.0 (1)
     543-549  E7.1  mW/m2 E_F1.0-2.0  Positive uncertainty in F1.0-2.0
     551-558  E8.1  mW/m2   F2.0-4.0  Energy flux in 2.0-4.0 keV band (2)
     560-566  E7.1  mW/m2 e_F2.0-4.0  [2.6e-16/99] Negative uncertainty
                                       in F2.0-4.0 (1)
     568-574  E7.1  mW/m2 E_F2.0-4.0  Positive uncertainty in F2.0-4.0
     576-583  E8.1  mW/m2   F2.0-8.0  Energy flux in 2.0-8.0 keV band (2)
     585-591  E7.1  mW/m2 e_F2.0-8.0  [5e-16/99] Negative uncertainty
                                       in F2.0-8.0 (1)
     593-599  E7.1  mW/m2 E_F2.0-8.0  Positive uncertainty in F2.0-8.0
     601-608  E8.1  mW/m2   F4.0-8.0  Energy flux in 4.0-8.0 keV band (2)
     610-616  E7.1  mW/m2 e_F4.0-8.0  [5.8e-16/99] Negative uncertainty
                                       in F4.0-8.0 (1)
     618-624  E7.1  mW/m2 E_F4.0-8.0  Positive uncertainty in F4.0-8.0
     626-632  E7.1  mW/m2   F0.2-4.5  Energy Flux in 0.2-4.5 keV band (2)
     634-638  E5.0  mW/m2 e_F0.2-4.5  Negative uncertainty in F0.2-4.5
     640-644  E5.0  mW/m2 E_F0.2-4.5  Positive uncertainty in F0.2-4.5
     646-649  I4    ---    [SPH2011]  [1197/1881]? Matched source identifier in S11
                                        (Stiele+ 2011, J/A+A/534/A55)
     651-659  A9    ---     Class     Source classification
                                        in Stiele+ 2011, J/A+A/534/A55
         661  A1    ---     PHAT      Single letter PHAT counterpart code (3)
     663-666  F4.2  mag     Av        [0.02/3.9]? Mean extinction from maps of
                                        Dalcanton+ (2015ApJ...814....3D)
     668-751  A84   ---     Notes     Notes from visual inspection of PHAT images

    Note (1): When the negative uncertainty is equal to 99 it indicates that this
              is an upper-limit measurement.
    Note (2): In erg/cm2/s.
              0.35-8.0keV energy flux = (Count Rate * 1.313e-11);
              0.35-1.0keV energy flux = (Count Rate * 1.767e-11);
              0.5-8.0keV energy flux  = (Count Rate * 1.272e-11);
              0.5-1.0keV energy flux  = (Count Rate * 1.438e-10);
              1.0-2.0keV energy flux  = (Count Rate * 5.620e-12);
              2.0-4.0keV energy flux  = (Count Rate * 1.443e-11);
              2.0-8.0keV energy flux  = (Count Rate * 2.138e-11);
              4.0-8.0keV energy flux  = (Count Rate * 3.487e-11);
              0.2-4.5keV energy flux  = (0.35-8.0keV Count Rate * 9.416e-12).
    Note (3): Code as follows:
        n = none (185 occurrences);
        g = galaxy (107 occurrences);
        p = point/star (58 occurrences);
        f = foreground (12 occurrences);
        s = SNR (6 occurrences);
        c = cluster (5 occurrences).

    Byte-by-byte Description of file:  table6.dat

       Bytes Format Units   Label     Explanations

       1- 18  A18   ---     CXO       Unique source identifier
                                        (HHMMSS.ss+DDMMSS.s; J2000)
          20  A1    ---     f_CXO     Flag on CXO (1)
      22- 30  F9.6  deg     RAXdeg    [10.9/11.8] CXO right ascension (J2000)
      32- 40  F9.6  deg     DEXdeg    [41.2/42.3] CXO declination (J2000)
      42- 45  F4.2  arcsec  ePos      [0.2/4.6] X-ray source position uncertainty
                                        from Table 4
      47- 55  F9.6  deg     RAdeg     [10.9/11.8] PHAT right ascension (J2000)
      57- 65  F9.6  deg     DEdeg     [41.2/42.3] PHAT declination (J2000)
      67- 72  F6.3  mag     F275W     [18.6/27.5]?=99.999 HST//WFC3 F275W band
                                        magnitude
      74- 78  F5.2  mag     F336W     [19/25.2] HST/WFC3 F336W band magnitude
      80- 85  F6.3  mag     F475W     [20.2/26.2]?=99.999 HST/ACS F475W band
                                        magnitude
      87- 91  F5.2  mag     F814W     [17.3/24.6] HST/ACS F814W band magnitude
      93- 98  F6.3  mag     F110W     [16.2/25.8]?=99.999 HST/WFC3 F110W band
                                        magnitude
     100-105  F6.3  mag     F160W     [15.4/25.5]?=99.999 HST/WFC3 F160W band
                                        magnitude
     107-113  E7.2  mW/m2   F0.35-8   [1.8e-15/1.3e-13] Flux in 0.35-8keV band
     115-119  E5.1  mW/m2  e_F0.35-8  F0.35-8 negative uncertainty
     121-125  E5.1  mW/m2  E_F0.35-8  F0.35-8 positive uncertainty

    Note (1): Flag as follows:
     a = Included in the "best candidate" sample. CXO J004339.06+412117.6 is
          considered such a candidate, but no SFH is available.
     c = No local young population detected.

    Byte-by-byte Description of file:  table7.dat

       Bytes Format Units   Label    Explanations

       1- 18  A18   ---     CXO      Catalog identifier (HHMMSS.ss+DDMMSS.s; J2000)
          19  A1    ---     ---      [,]
      21- 24  F4.1  Myr     LowAge   [4/63.1] Lower edge of the age bin (1)
      26- 29  F4.1  Myr     HighAge  [5/79.4] Higher edge of the age bin (1)
      31- 35  F5.3  ---     Prob     [0/1] Probability HMXB system is in the age bin
      37- 41  F5.3  ---     E_Prob   Positive uncertainty in Prob
      43- 47  F5.3  ---     e_Prob   Negative uncertainty in Prob

    Note (1): For example, if low age is 4.0 and high age is 5.0, then the Prob
              column refers to the probability that the HMXB candidate has an age
              between 4.0 and 5.0Myr.

    History:
        From electronic version of the journal
    ================================================================================
    (End)                  Prepared by [AAS], Emmanuelle Perret [CDS]    20-Dec-2018