ACDS V10.0 - Detailed Description of J/ApJS/157/59

ACDS V10.0 - Mon Jan 20 00:15:50 CET 2025

| # Detailed Description of J/ApJS/157/59 : Ultraluminous X-ray sources in nearby galaxies (Liu+, 2005) |

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/157/59      Ultraluminous X-ray sources in nearby galaxies   (Liu+, 2005)
    ================================================================================
    Ultraluminous X-ray sources in nearby galaxies from ROSAT High Resolution Imager
    observations.
    I. Data analysis.
        Liu J.-F., Bregman J.N.
       <Astrophys. J. Suppl. Ser., 157, 59-125 (2005)>
       =2005ApJS..157...59L
    ================================================================================
    ADC_Keywords: X-ray sources ; Binaries, X-ray ; Galaxies, nearby

    Keywords: catalogs - galaxies: general - X-rays: binaries - X-rays: galaxies

    Abstract:
        X-ray observations have revealed in other galaxies a class of
        extranuclear X-ray point sources with X-ray luminosities of
        1039-1041ergs/s, exceeding the Eddington luminosity for stellar
        mass X-ray binaries. These ultraluminous X-ray sources (ULXs) may be
        powered by intermediate-mass black holes of a few thousand MSun or
        stellar mass black holes with special radiation processes. In this
        paper, we present a survey of ULXs in 313 nearby galaxies with D25>1
        within 40Mpc with 467 ROSAT High Resolution Imager (HRI) archival
        observations. The HRI observations are reduced with uniform
        procedures, refined by simulations that help define the point source
        detection algorithm employed in this survey. A sample of 562
        extragalactic X-ray point sources with LX=1038-1043ergs/s is
        extracted from 173 survey galaxies, including 106 ULX candidates
        within the D25 isophotes of 63 galaxies and 110 ULX candidates
        between 1D25 and 2D25 of 64 galaxies, from which a clean sample of
        109 ULXs is constructed to minimize the contamination from foreground
        or background objects.

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × table1.dat        98      312   Properties of surveyed galaxies
    × table2.dat       101      562   X-ray sources in surveyed galaxies
    × table3.dat       110      604   Individual observations for ULX candidates

    See also:
      IX/28          : ROSAT HRI Pointed Observations (1RXH) (ROSAT Team, 2000)
      VII/155        : RC3 (de Vaucouleurs+ 1991)
      J/ApJS/154/519 : Properties of ultraluminous X-ray candidates (Swartz+, 2004)
      J/A+A/429/1125 : Catalog of Ultraluminous X-ray sources (Liu+, 2005)

    Byte-by-byte Description of file:  table1.dat

       Bytes Format Units    Label   Explanations

       1-  9  A9    ---      Galaxy  Galaxy name
      11- 16  F6.2  deg      GLON    Galactic longitude of the galaxy
      18- 23  F6.2  deg      GLAT    Galactic latitude of the galaxy
      25- 28  F4.1  arcmin   D25     Major axis of the D25 isophotal ellipsis
      30- 33  F4.1  arcmin   d25     Minor axis of the D25 isophotal ellipsis
      35- 41  E7.3  cm-2     nH      Galactic HI column density (1)
      43- 48  F6.3  Mpc      Dist    Distance
      50- 52  A3    ---      r_Dist  Reference on Dist (2)
      54- 62  A9    ---      MType   The RC3 morphological type (3)
      64- 67  F4.1  ---      HType   ? The RC3 Hubble T type
      69- 74  E6.2  solLum   LBlue   ? The Blue luminosity (4)
          76  A1    ---     l_F60um  Limit flag on F60um
      77- 85  F9.4  Jy       F60um   The 60µm flux density (5)
          87  A1    ---    l_FIRMAG  Limit flag on FIRMag
      88- 92  F5.1  mag      FIRMAG  Absolute FIR magnitude (6)
      94- 98  A5    ---      Flag    HII/starburst galaxy high star formation rate

    Note (1): Taken from the dust map by Dickey & Lockman (1990ARA&A..28..215D).

    Note (2): Reference on Dist, defined as follows:
        KP  = Key Project (Freedman et al., 2001ApJ...553...47F);
        SBF = Surface brightness fluctuation method (Tonry et al.,
               2001ApJ...546..681T);
        T92 = Nearby galaxy flow model by Tully (1992, Cat. J/ApJS/80/479);
        T88 = Nearby Galaxy Catalog (Tully 1988, Cat. VII/145);
        NED = Recessional velocities taken from the NED (V3K) service (RC3).
    Note (3): In the type code, S stands for spiral, E for elliptical, S0 for
              lenticular, I for irregular; (r) for inner ring, (s) for S-shaped,
              (rs) for mixed; B for barred, A for non-barred, AB for mixed; Im
              for magellanic irregular, I0 for non-magellanic irregular; the
              trailing -/o/+ for early/intermediate/late stage;  etc. The detailed
              explanations can be found in the RC3 (Cat. VII/155) catalogue
              (p. 15, Vol. I).
    Note (4): Calculated from the apparent blue magnitude taken from RC3. The
              luminosity is expressed in unit of solar luminosity assuming a
              absolute blue magnitude of 5.47 for the Sun.
    Note (5): Taken from the IRAS point source catalog (IPAC, 1986, Cat. II/125),
              with some nearby galaxies from Rice et al. (1988, Cat. VII/109).
              When the galaxy is below detection, the 3{sigma} upper limit is
              calculated by adopting noise levels of 8.5mJy/arcmin2 for 60µm
              (Rice et al. 1988, Cat. VII/109).
    Note (6): Computed from the flux densities at 60µm and 100µm as
              prescribed in RC3 (Cat. VII/155). A leading "<" means the magnitude
              is computed from the upper limits of the flux densities.

    Byte-by-byte Description of file:  table2.dat

       Bytes Format Units   Label     Explanations

       1-  9  A9    ---     Galaxy    Galaxy name (1)
      11- 13  A3    ---     XName     X-ray source name (1)
      15- 16  I2    h       RAh       Hour of Right Ascension (J2000)
      18- 19  I2    min     RAm       Minute of Right Ascension (J2000)
      21- 25  F5.2  s       RAs       Second of Right Ascension (J2000)
          27  A1    ---     DE-       Sign of the Declination (J2000)
      28- 29  I2    deg     DEd       Degree of Declination (J2000)
      31- 32  I2    arcmin  DEm       Arcminute of Declination (J2000)
      34- 37  F4.1  arcsec  DEs       Arcsecond of Declination (J2000)
          39  I1    ---     Nc        Number of X-ray sources identified (2)
      41- 46  F6.1  arcsec  r         Nuclear offset
      48- 51  F4.2  ---     r/R25     Nuclear offset in unit of elliptical radius R25
      53- 57  F5.1  ---     s-Max     Maximum detection significance among observations
      59- 68  F10.4 10+32W  Lum       Maximum luminosity among all observations (3)
          70  I1    ---     Nv        ? Number of observations in which the probability
                                   for the Kolmogorov-Smirnov test of the source
                                   being constant is less than 0.01 (4)
          72  A1    ---     Env       Environments of the X-ray source (5)
      74- 89  A16   ---     ID        Identification of the X-ray source (6)
      91- 96  A6    ---     ULX       Source flag (7)
      98-101  A4    ---     UName     ULX name in the clean ULX sample

    Note (1): [LB2005] NGC NNNN XNN, [LB2005] NGC NNNNA XN, and
              [LB2005] PGC NNNNN XNN in Simbad.
    Note (2): With objects in astrometric catalogs used to correct the
              X-ray positions.
    Note (3): The X-ray luminosities are computed using a power-law spectrum
              between 0.3-8keV with a photon index of 1.7.
    Note (4): i.e., the source is highly variable during the observation.

    Note (5): Environments of the X-ray source, defined as follows:
        D = the source is in a dusty region usually associative of
            star forming activities.
        S = the source is associated with spiral arms.
    Note (6): Identification of the X-ray source, with symbols:
        *      = the source is a bright foreground star;
        P/(Pr) = the source is positionally coincident with a point source
                 in optical/IR/(Radio);
        mP     = the source is close to multiple such point sources and unique
                 identification requires better positions;
        Z      = the source is close to faint fuzzy features on the optical image.
        ()     = Identification enclosed with parentheses when it is within the
                 host galaxy.
    Note (7): This indicates whether the source is a nuclear source (N) or a
              ULX candidate (ULX).  Prefix '1' stands for ULXs within the D25
              isophote of the galaxy, '2' for ULXs between 1D25 and 2D25, and
              'E' for ULXs with LX>1040erg/s. Suffix 'd' stands for ULXs that
              are above 1039erg/s in the deepest observation for the galaxy.

    Byte-by-byte Description of file:  table3.dat

       Bytes Format Units    Label   Explanations

       1-  9  A9    ---      Galaxy  Galaxy name (1)
      11- 14  A4    ---      Name    Source name (1) (2)
      16- 30  A15   ---      Obs     Individual observation (3)
      32- 36  I5    d        MJD     Observation date in MJD (JD-2400000.5)
      38- 42  F5.1  ks      ExpTime  Exposure time
      44- 47  F4.1  ---      DelD    Time duration of the observation
          48  A1    ---      x_DelD  [dh] Units for DelD value: days (d), hours (h)
          50  A1    ---     l_sigma  Limit flag on sigma
      51- 55  F5.1  ---      sigma   Detection significance
      57- 61  F5.2  arcmin   theta   ? Off-axis angle
      63- 66  F4.2  ---      C       ? Correction factor based on the simulations
          68  A1    ---    l_CorCnt  Limit flag on CorCnt
      69- 74  F6.1  ct       CorCnt  X-ray source count corrected by applying C
      76- 80  F5.2  %      e_CorCnt  ? Fractional error for the corrected count
          82  A1    ---      l_Flux  Limit flag on Flux
      83- 90  E8.3  mW/m2    Flux    Flux in units of erg/s/cm2 (4)
          92  A1    ---      l_LX    Limit flag on LX
      93-101  F9.4  10+32W   LX      ? X-ray luminosity in units of 10+39erg/s (5)
     104-110  E7.2  ---      PKS     ? Non-variability test probability (6)

    Note (1): [LB2005] NGC NNNN ULXN, [LB2005] NGC NNNNA ULXN,
              [LB2005] PGC NNNNN ULXN, in Simbad.
    Note (2): The source name refers to UName (table2.dat) if it starts with 'ULX',
              to XName (table2.dat) otherwise.
    Note (3): Suffixed is the sequence number in the source list from wavdetect.
              'U' is suffixed when the source is below 3{sigma} detection in the
              observation. '+' is suffixed if the observation has the deepest
              sensitivity for the host galaxy.
    Note (4): Computed with the corrected source count, by assuming a power-law
              spectrum between 0.3-8keV with a photon index of 1.7.
    Note (5): Computed from the flux by assuming a distance to the host galaxy.

    Note (6): The probability for the Kolmogorov-Smirnov test null hypothesis
              that the source is constant during the observation.

    History:
        From electronic version of the journal
    ================================================================================
    (End)                   Greg Schwarz [AAS], Marianne Brouty [CDS]    04-Aug-2005