Access to Astronomical Catalogues

J/MNRAS/318/1073        Hard spectrum ROSAT sources. I.            (Page+, 2000)
A survey of hard spectrum ROSAT sources - I. X-ray source catalogue.
    Page M.J., Mittaz J.P.D., Carrera F.J.
   <Mon. Not. R. Astron. Soc. 318, 1073 (2000)>
   =2000MNRAS.318.1073P
ADC_Keywords: X-ray sources - Surveys

Keywords: catalogues - surveys - X-rays: general


Abstract:
    We present a catalogue of 147 serendipitous X-ray sources selected to
    have hard spectra (α<0.5) from a survey of 188 ROSAT fields.
    Such sources must be the dominant contributors to the X-ray background
    at faint fluxes. We have used Monte Carlo simulations to verify that
    our technique is very efficient at selecting hard sources: the survey
    has ≥10 times as much effective area for hard sources as it has for
    soft sources above a 0.5-2keV flux level of 10-14erg/cm2/s. The
    distribution of best-fitting spectral slopes of the hard sources
    suggests that a typical ROSAT hard source in our survey has a spectral
    slope α∼0. The hard sources have a steep number flux relation
    (dN/dSµS-γ with a best-fitting value of
    γ=2.72±0.12) and make up about 15 per cent of all 0.5-2keV
    sources with S>10-14erg/cm2/s. If their N(S) continues to fainter
    fluxes, the hard sources will comprise ∼40 per cent of sources with
    5x10-15<S<10-14erg/cm2/s. The population of hard sources can
    therefore account for the harder average spectra of ROSAT sources with
    S<10-14erg/cm2/s. They probably make a strong contribution to the
    X-ray background at faint fluxes and could be the solution to the
    X-ray background spectral paradox.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat       127      147   Hard source catalogue


See also:
   IX/30 : Second ROSAT PSPC Catalog (ROSAT, 2000)


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

   Bytes Format Units      Label   Explanations

   1-  3  A3    ---        ---     [RXJ]
   4- 21  A18   ---        RXJ     Source name based on J2000 coordinates of
                                   ROSAT source from PSS (1)
  23- 33  A11   ---        ROR     ROSAT observation in which source was
                                    detected
  35- 38  F4.1  ks        ExpTime  ROSAT PSPC exposure time after good time
                                   screening
  40- 43  F4.1  arcmin    OffAxis  Off-axis angle of source
  45- 48  F4.1  arcsec     ePos    Positional uncertainty of source from PSS
  50- 53  F4.1  ---        sigma   PSS significance of source above background
                                    level
  55- 58  F4.1  ---        PSF     Spread function to the source radial profile
                                    in 5" bins out to 1', from a fit of the
                                    model PSPC point
  60- 61  I2    arcsec     Rad     Source circle radius for extraction of the
                                    three-colour spectrum
  63- 65  I3    ct         C1      Number of counts in PSPC channels 11-41
                                    (0.1-0.4keV) within the source circle
  67- 69  I3    ct         C2      Number of counts in PSPC channels 52-90
                                    (0.5-0.9keV] within the source circle
  71- 73  I3    ct         C3      Number of counts in PSPC channels 91-201
                                    (0.9-2.0 keV) within the source circle
  75- 79  F5.1  ct         B1      Expected number of background counts in PSPC
                                    channels 11-41 within the source circle
  81- 85  F5.1  ct         B2      Expected number of background counts in PSPC
                                    channels 52-90 within the source circle
  87- 90  F4.1  ct         B3      Expected number of background counts in PSPC
                                    channels 91-201 within the source circle
  92- 96  F5.2  ---        alpha   Fitted power-law spectral slope
  98-101  F4.2  ---       E_alpha  68% uncertainty in alpha (upper limit)
 103-106  F4.2  ---       e_alpha  68% uncertainty in alpha (lower limit)
 108-111  F4.2  ---        Prob    Probability of source having spectral slope
                                   alpha<(harder than) 0.5
 113-117  F5.2  10-17W/m2  S0.5-2  0.5-2keV flux (3)
 119-121  F3.1  10-17W/m2 E_S0.5-2  68% uncertainty on S0.5-2 (upper limit) (3)
 123-125  F3.1  10-17W/m2 e_S0.5-2  68% uncertainty on S0.5-2 (lower limit) (3)
     127  A1    ---        Flag    [SI] Optical counterpart flag (2)

Note (1): Sources identified as [PMC2000] RX JHHMMSS.ss+DDMMSS.s in Simbad

Note (2): Optical counterpart flag as follows:
      S = means spectroscopic sample
      I = means imaging sample
Note (3): in 10-14erg/cm2/s



History:
    From electronic version of the journal and prepared via OCR at CDS.
(End)                         James Marcout, Patricia Bauer [CDS]    28-Mar-2001