ACDS V10.0 - Detailed Description of J/MNRAS/289/263

ACDS V10.0 - Wed Jan 29 14:11:30 CET 2025

| # Detailed Description of J/MNRAS/289/263 : Galaxy clusters from the APM galaxy survey (Dalton+ 1997) |

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/MNRAS/289/263     Galaxy clusters from the APM galaxy survey  (Dalton+ 1997)
    ================================================================================
    The APM galaxy survey - V. Catalogues of galaxy clusters.
           Dalton G.B., Maddox S.J., Sutherland W.J., Efstahiou G.
          <Mon. Not. R. Astron. Soc. 289, 263 (1997)>
          =1997MNRAS.289..263D      (SIMBAD/NED BibCode)
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    ADC_Keywords: Clusters, galaxy

    Keywords: catalogues - surveys - galaxies: clusters: general -
              large-scale structure of the Universe

    Abstract:
        We describe the construction of catalogues of galaxy clusters from the
        APM Galaxy survey using an automated algorithm based on Abell-like
        selection criteria. We investigate the effects of varying several
        parameters in our selection algorithm, including the magnitude range
        and radius from the cluster centre used to estimate the cluster
        richnesses. We quantify the accuracy of the photometric distance
        estimates by comparing them with measured redshifts, and we
        investigate the stability and completeness of the resulting
        catalogues. We find that the angular correlation functions for
        different cluster catalogues are in good agreement with one another,
        and are also consistent with the observed amplitude of the spatial
        correlation function of rich clusters.

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × catalog           57      957   The APM cluster catalogue

    See also:
       J/MNRAS/278/1025 : The APM Bright Galaxy Catalogue (Loveday 1996)
       J/MNRAS/246/433  : APM galaxy survey. II. (Maddox+ 1990)
       J/MNRAS/269/151  : APM galaxy survey. IV. (Dalton+, 1994)
       J/MNRAS/274/1071 : Edinburgh-Milano cluster redshift survey (Collins+ 1995)
               VII/203  : Las Campanas Redshift Survey (Shectman+ 1996)

    Byte-by-byte Description of file:  catalog

       Bytes Format Units   Label     Explanations

       1-  3  I3    ---     Cluster   Cluster number
       5-  6  I2    h       RAh       Right ascension (1950)
       7-  8  I2    min     RAm       Right ascension (1950)
       9- 12  F4.1  s       RAs       Right ascension (1950)
          14  A1    ---     DE-       Declination sign
      15- 16  I2    deg     DEd       Declination (1950)
      17- 18  I2    arcmin  DEm       Declination (1950)
      19- 20  I2    arcsec  DEs       Declination (1950)
      22- 26  F5.2  mag     Xmag      X magnitude (1)
      28- 31  F4.1  arcmin  rC        Projected radius
      33- 37  F5.3  ---     z         Estimated redshift determined from Xmag
      39- 43  F5.1  ---     R         Cluster richness
          44  A1    ---     n_R       [abc] Notes (2)
      46- 50  F5.3  ---     zabs      ? Absorption redshift
      52- 56  A5    ---     n_zabs    [12345+, ] Notes (3)

    Note (1): We define Xmag to be the magnitude for which Ci=X, i.e. in the case
               of X=10 with no weighting then Xmag is exactly equivalent to Abell's
               m10.  (Ci is the weighted sum of galaxies brighter than mi
               minus the expected background count brighter than mi.)
    Note (2): a: This cluster is close to a bright star which has been excised from
                  the galaxy catalogue. A part of the cluster area is therefore
                  missing from the survey data and so the richness may have been
                  underestimated.
              b: The field of this cluster includes a 2-arcmin foreground galaxy
                  0.7rC from the centre which has been broken up into several
                  small galaxian images by the APM software. These additional
                  objects may have caused the richness to be slightly overestimated.
              c: This field is dominated by a 2-arcmin foreground galaxy which has
                  been broken up into several small galaxian images by the APM
                  software. The field does not appear to contain a true cluster. The
                  cluster was below the richness threshold used by Dalton et al.
                  (1994MNRAS.271L..47D) and was not visually inspected at the time
                  of those observations.
    Note (3): 1: Redshift from Paper IV, Dalton et al., 1994, Cat. J/MNRAS/269/151
              2: Redshift measured by Dalton et al. (1994MNRAS.271L..47D). Note that
                  this survey was limited to Xmag <=19.2
              3: Redshift measured as part of the deep extension to the APM cluster
                  redshift survey (Croft et al., 1997, MNRAS, in press)
              4: Cluster found in the Edinburgh-Milano Cluster Redshift Surcey
                  (Collins et al., 1995, Cat. J/MNRAS/274/1071). If only one
                  references is present then the redshift is adopted from this
                  source, otherwise this entry indicates that the cluster is also
                  found in that survey.
              5: Cluster redshift has been drawn from Las Campanas Redshifdt Survey
                  (LCRS: Schectman et al., 1996ApJ...470..172S. Cat. VII/203)
              +: For the cluster APM 100, we have adopted the value given by
                  Collins et al. (1995, Cat. J/MNRAS/274/1071) as they point out
                  this is in better agreement with the maximum likelihood redshift
                  estimate quoted in Paper IV (Cat. J/MNRAS/269/151) than our
                  single galaxy redshift.

    Acknowledgements: Gavin Dalton g.dalton1@physics.ox.ac.uk

    References:
       Maddox et al., Paper I.           1990MNRAS.243..692M
       Maddox et al., Paper II.          1990MNRAS.246..433M, Cat. J/MNRAS/246/433
       Maddox et al., Paper III.         1996MNRAS.283.1227M
       Dalton et al., Paper IV.          1994MNRAS.269..151D, Cat. J/MNRAS/269/151
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    (End)                                          Patricia Bauer [CDS]  10-Oct-1997