ACDS V10.0 - Detailed Description of II/156A

ACDS V10.0 - Sun Jan 19 02:08:14 CET 2025

| # Detailed Description of II/156A : IRAS Faint Source Catalog, |b| > 10, Version 2.0 (Moshir+ 1989) |

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.

    II/156A     IRAS Faint Source Catalog, |b| > 10, Version 2.0 (Moshir+ 1989)
    ================================================================================
    IRAS Faint Source Catalog, |b| > 10 Degrees, Version 2.0
        Moshir, M., Copan, G., Conrow, T., McCallon, H., Hacking, P., Gregorich, D.,
        Rohrbach, G., Melnyk, M., Rice, W., Fullmer, L., and Chester, T.J.
       <Infrared Processing and Analysis Center (1989)>
       =1990IRASF.C......0M
    ================================================================================
    ADC_Keywords: Infrared sources ; Photometry, infrared ; Surveys

    Mission_Name: IRAS

    Description:
        The Faint Source Survey (FSS) is the definitive Infrared Astronomical
        Satellite data set for faint point sources. The FSS was produced by
        point-source filtering the individual detector data streams and then
        coadding those data streams using a trimmed-average algorithm. The
        resulting images, or plates, give the best estimate from the IRAS
        survey data of the point source flux density at every surveyed point
        of the sky. The Faint Source Catalog (FSC) is a compilation of the
        sources extracted from the FSS plates that have met reasonable
        reliability requirements. Averaged over the whole catalog, the FSC is
        at least 98.5% reliable at 12 and 25 microns, and ~94% at 60 microns.
        For comparison, the IRAS Point Source Catalog (PSC) is >99.997%
        reliable, but the sensitivity of the FSC exceeds that of the PSC by
        about a factor of 2.5. The FSC contains data for 173,044 point sources
        in unconfused regions with flux densities typically above 0.2 Jy at
        12, 25, and 60 microns, and above 1.0 Jy at 100 microns. The FSS
        plates are somewhat more sensitive but less reliable than the FSC;
        typically, only sources with SNR>5-6 in the plates are contained in
        the FSC. Sources with SNR>3 but which do not meet the reliability
        requirements of the FSC are catalogued in the Faint Source Reject File
        (FSR, Cat. II/275). The data products, the processing methods used to
        produce them, results of an analysis of these products, and cautionary
        notes are given in the Explanatory Supplement to the IRAS Faint Source
        Survey (see references in fsc.txt).

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × fsc.txt           84      897   Original description (ADC CD-ROM Vol. 1, 1991)
    × SIMPLE.fih        80       60   FITS header
    × main.dat         227   173044   IRAS Faint Sources
    × main.fih          80      306   associated FITS header
    × assoc.dat         64   235935   Associations
    × assoc.fih         79       94   associated FITS header
    × meaning.txt       80      304   Details of association catalogues
    × tofits.sh         80       74   Unix shell to generate FITS (1)

    Note (1): This small script should run on any Unix platform.
        To generate the FITS version of the tables, execute
        ./tofits main > main.fits       (for the main table)
        ./tofits assoc  > assoc.fits    (for the association file)

    See also:
      II/125  : IRAS Point Source Catalog (IRAS-PSC)
      II/126  : IRAS Serendipitous Survey Catalog (IRAS-SSC, sources SHHMMm+DDMMA)
      II/274  : IRAS Point Source Reject Catalog (IRAS-PSR, sources RHHMMm+DDMM)
      II/275  : IRAS Faint Source Reject Catalog (sources IRAS ZHHMMm+DDMMA)
      VII/73  : IRAS Small Scale Structure Catalog (IRAS-SSSC, sources XHHMM+DDd)
      II/174  : IRAS 2Jy Redshift Survey Data File
      II/190  : IRAS Minor Planet Survey Data Base
      VII/91  : IRAS Asteroid and Comet Survey
      VII/109 : IRAS Observations of Large Optical Galaxies
      VII/113 : Catalogued Galaxies + QSOs observed in IRAS Survey

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

       Bytes Format  Units   Label    Explanations

       1- 12  A12    ---     IRAS     IRAS faint source name (starts by F)
      13- 14  I2     h       RAh      Hours RA, equinox 1950.0, epoch 1983.5
      15- 16  I2     min     RAm      Minutes RA, equinox 1950.0, epoch 1983.5
      17- 19  I3     0.1s    RAds     Deci-seconds RA
          20  A1     ---     DE-      Sign of DEC, equinox 1950.0, epoch 1983.5
      21- 22  I2     deg     DEd      Degrees Dec, equinox 1950.0, epoch 1983.5
      23- 24  I2     arcmin  DEm      Minutes Dec, equinox 1950.0, epoch 1983.5
      25- 26  I2     arcsec  DEs      Seconds Dec, equinox 1950.0, epoch 1983.5
      27- 29  I3     arcsec  Major    Uncertainty ellipse major axis
      30- 32  I3     arcsec  Minor    Uncertainty ellipse minor axis
      33- 35  I3     deg     PosAng   Uncertainty ellipse position angle
      36- 38  I3     ---     o_Fnu12  ? Number of times observed at 12um
      39- 41  I3     ---     o_Fnu25  ? Number of times observed at 25um
      42- 44  I3     ---     o_Fnu60  ? Number of times observed at 60um
      45- 47  I3     ---    o_Fnu100  ? Number of times observed at 100um
      48- 56  E9.3   Jy      Fnu12    Non-color corrected flux density at 12um
      57- 65  E9.3   Jy      Fnu25    Non-color corrected flux density at 25um
      66- 74  E9.3   Jy      Fnu60    Non-color corrected flux density at 60um
      75- 83  E9.3   Jy      Fnu100   Non-color corrected flux density at 100um
          84  I1     ---     q_Fnu12  Flux density quality at 12um
          85  I1     ---     q_Fnu25  Flux density quality at 25um
          86  I1     ---     q_Fnu60  Flux density quality at 60um
          87  I1     ---    q_Fnu100  Flux density quality at 100um
      88- 90  I3     %       e_Fnu12  Relative flux density uncertainty at 12um
      91- 93  I3     %       e_Fnu25  Relative flux density uncertainty at 25um
      94- 96  I3     %       e_Fnu60  Relative flux density uncertainty at 60um
      97- 99  I3     %      e_Fnu100  Relative flux density uncertainty at 100um
     100-101  I2     %       Rel      Percent minimum source reliability
     102-108  E7.1   ---     SNR12    ? Signal/Noise ratio at 12um
     109-115  E7.1   ---     SNR25    ? Signal/Noise ratio at 25um
     116-122  E7.1   ---     SNR60    ? Signal/Noise ratio at 60um
     123-129  E7.1   ---     SNR100   ? Signal/Noise ratio at 100um
     130-136  E7.1   ---    locSNR12  ? Local Signal/Noise ratio at 12um
     137-143  E7.1   ---    locSNR25  ? Local Signal/Noise ratio at 25um
     144-150  E7.1   ---    locSNR60  ? Local Signal/Noise ratio at 60um
     151-157  E7.1   ---   locSNR100  ? Local Signal/Noise ratio at 100um
     158-160  I3     pix     A12      ? Number of pixels above threshold at 12um
     161-163  I3     pix     A25      ? Number of pixels above threshold at 25um
     164-166  I3     pix     A60      ? Number of pixels above threshold at 60um
     167-169  I3     pix     A100     ? Number of pixels above threshold at 100um
     170-171  I2     ---     Ncat     Number of nearby catalog sources (6')
     172-173  I2     ---     Nx12     Number of nearby extractions at 12 um
     174-175  I2     ---     Nx25     Number of nearby extractions at 25 um
     176-177  I2     ---     Nx60     Number of nearby extractions at 60 um
     178-179  I2     ---     Nx100    Number of nearby extractions at 100 um
     180-181  I2     ---     Cir1     Number of nearby 100 um-only extractions
     182-183  I2     ---     Conf     Confusion flag, 1 per band, bit-encoded (1)
     184-188  F5.2   ---     NoisC12  ? Noise correction factor at 12um
     189-193  F5.2   ---     NoisC25  ? Noise correction factor at 25um
     194-198  F5.2   ---     NoisC60  ? Noise correction factor at 60um
     199-203  F5.2   ---    NoisC100  ? Noise correction factor at 100um
     204-205  I2     ---     nID      ? Number of positional associations
     206-207  I2     ---     Type     ? Type of associated object (G1)
     208-212  F5.3   ---     NoisR12  ? Ratio of 85% to 68% quantiles of flux
                                        distribution at 12um
     213-217  F5.3   ---     NoisR25  ? Ratio of 85% to 68% quantiles of flux
                                        distribution at 25um
     218-222  F5.3   ---     NoisR60  ? Ratio of 85% to 68% quantiles of flux
                                        distribution at 60um
     223-227  F5.3   ---    NoisR100  ? Ratio of 85% to 68% quantiles of flux
                                        distribution at 100um

    Note (1): corresponding to 12, 25, 60 and 100um from lowest to highest bit.
         Therefore the confusion flags are set in the bands as follows:
          1 = confusion in 12um band
          2 = confusion in 25um band
          4 = confusion in 60um band
          8 = confusion in 100um band
         Confusion in multiple bands are expressed by a sum of the values,
         e.g. 12 (8+4) means a confusion in 60 and 100µm bands.

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

       Bytes Format  Units   Label    Explanations

       1- 12  A12    ---     IRAS     IRAS source name
      13- 18  I6     ---     RecNo    Main data table record number for IRAS source
      19- 20  I2     ---     catID    Catalog number, details in file "meaning.txt"
      21- 35  A15    ---     Source   Source identification
      36- 40  A5     ---     Type     Source type or spectral class, or association
                                      catalog type (G1)
      41- 43  I3     arcsec  Dist     Distance of IRAS source to association
      44- 46  I3     deg     dPA      Position angle from IRAS source to association
      47- 49  I3     arcsec  dMaj     Distance from IRAS source to association
                                      along major axis of IRAS uncertainty ellipse
      50- 52  I3     arcsec  dMin     Distance from IRAS source to association
                                      along minor axis of IRAS uncertainty ellipse
      53- 56  I4     ---     Field1   ?=-999 Object data field 1, catalog dependent
      57- 60  I4     ---     Field2   ?=-999 Object data field 2, catalog dependent
      61- 64  I4     ---     Field3   ?=-999 Object data field 3, catalog dependent

    Global Notes:

    Note (G1): Type ranges from 1 to 15 and states whether an association
        was found in:
          * a stellar catalogue (bit 0 = 1)      (*)
          * an extragalactic catalog (bit 1 = 2) (*)
          * catalogs with other types of objects (bit 2 = 4) or
          * in a catalog with mixed types (bit 3 = 8).
        For example, if associations were found to both an extragalactic
        catalog and a stellar catalog, Type is set to 3 (2+1).

        (*) The meaning of these two bits are different from what is stated
            in the original documentation "fsc.txt" file.

    History:
      * Original description from Susan Gessner (NASA/GSFC) in 1989
       (see file "fsc.txt")
      * 24-Feb-1993: standardized documentation at CDS
      * 30-Jan-2009: description homogenized with other IRAS catalogs at CDS.
    ================================================================================
    (End)                                                                24-Feb-1993