ACDS V10.0 - Detailed Description of J/AJ/115/2587

ACDS V10.0 - Sun Jan 19 03:00:17 CET 2025

| # Detailed Description of J/AJ/115/2587 : Einstein IPC database ultrasoft survey (Thompson+ 1998) |

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/AJ/115/2587       Einstein IPC database ultrasoft survey (Thompson+ 1998)
    ================================================================================
    Initial results of a comprehensive ultrasoft survey of the Einstein IPC
    database: source list and confirmation of the selection procedure.
         Thompson R.J., Shelton R.G., Arning C.A.
        <Astron. J. 115, 2587 (1998)>
        =1998AJ....115.2587T
    ================================================================================
    ADC_Keywords: X-ray sources

    Mission_Name: Einstein

    Keywords: binaries: close - pulsars: general - surveys - white dwarfs -
              X-rays

    Abstract:
        We have carried out a survey of the entire Einstein IPC database (a
        total of 5934 sources) to select objects with strong components of
        ultrasoft X-ray emission (i.e., emission below 0.5keV). The selection
        criteria are based on ratios of counts within three broad energy bands
        (i.e., X-ray "colors"). A total of 516 objects have been selected,
        with 202 (39%) having been identified through correlations with other
        databases. Of the currently identified objects, 45% are active
        galactic nuclei, 28% are stellar objects, 6% are "normal" galaxies and
        galaxy clusters, and the remaining 21% are "nonstellar" Galactic
        objects such as cataclysmic variables, pulsars, and white dwarfs. We
        present a discussion of the survey selection procedure, the list of
        selected sources, and discussions of interesting objects from the
        aforementioned groups. We discuss the remarkable success of our rather
        "low resolution" method of estimating spectral shape and present plans
        for follow-up studies of the as yet unidentified sources.

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × table1.dat        90      516   Source information, Part I
    × table2.dat        86      516   Source information, Part II

    See also:
       IX/13 : The 2E Catalogue (Harris+ 1994)

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

       Bytes Format Units     Label     Explanations

       1-  5  I5    ---       IPC       IPC number
       7-  8  I2    ---       Source    Object source number in the field
      10- 11  I2    h         RAh       Right ascension (J2000.0)
      13- 14  I2    min       RAm       Right ascension (J2000.0)
      16- 20  F5.2  s         RAs       Right ascension (J2000.0)
          22  A1    ---       DE-       Declination sign
      23- 24  I2    deg       DEd       Declination (J2000.0)
      26- 27  I2    arcmin    DEm       Declination (J2000.0)
      29- 33  F5.2  arcsec    DEs       Declination (J2000.0)
      35- 40  F6.2  10-3ct/s CountRate  Count rate over the 0.2-4keV passband
      43- 48  F6.3  10-3ct/s e_CountRate  rms uncertainty on CountRate
      50- 53  F4.1  ---       S/N       Signal-to-noise ration
      55- 58  I4    ---       RECO      ? Rib and edge code
      60- 90  A31   ---       Ident    *Identification of optical counterpart

    Note on Ident: one error corrected, see the "History" section below.

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

       Bytes Format Units    Label   Explanations

       1-  5  I5    ---      IPC     IPC number
       7-  8  I2    ---      Source  Object source number in the field
      10- 11  I2    h        RAh     Right ascension (J2000.0)
      13- 14  I2    min      RAm     Right ascension (J2000.0)
      16- 20  F5.2  s        RAs     Right ascension (J2000.0)
          22  A1    ---      DE-     Declination sign
      23- 24  I2    deg      DEd     Declination (J2000.0)
      26- 27  I2    arcmin   DEm     Declination (J2000.0)
      29- 33  F5.2  arcsec   DEs     Declination (J2000.0)
      35- 43  F9.3  ct       C1      Counts in the low (0.16-0.56keV) colour band
      45- 52  F8.3  ct       e_C1    rms uncertainty on C1
      54- 61  F8.3  ct       C2      Counts in the medium (0.56-1.08keV) colour band
      63- 69  F7.3  ct       e_C2    rms uncertainty on C2
      71- 78  F8.3  ct       C3      Counts in the high (1.08-3.5keV) colour band
      80- 86  F7.3  ct       e_C3    rms uncertainty on C3

    Table 3: Classes of objects
    -------------------------------------------------------------
      Class                                      Percentage of
                                               identified sources
    -------------------------------------------------------------
      Active galactic nuclei                        45
      Stellar                                       28
      Normal galaxies and galaxy clusters            6
      Cataclysmic variables (AM Herculis stars)      4
      PG 1159 objects/planetary nebulae              1
      DA white dwarfs                                9
      X-ray binaries                                 3
      Pulsars                                        1
      T Tauri stars                                  2
      W UMa variables/symbiotic stars                1

    History: From AJ electronic version
      * 27-Oct-1999: Corrected SAO number in table1 for source IPC 3727
        (is SAO 110135, not SAO 10135)
    ================================================================================
    (End)                           James Marcout, Patricia Bauer [CDS]  31-Aug-1998