Astronomical Data Center

ADCADC/CDS Standard Document for Catalog:
/catalogs/7/7004A/

The following is the "ReadMe" document that describes this ADC catalog. You can access the files described here in three ways:

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VII/4A              Abell and Zwicky Clusters of Galaxies          (Abell+ 1974)
================================================================================
Catalogue of Abell and Zwicky Clusters of Galaxies
     Abell G.O.
    <Astrophys. J. Suppl. Ser. 3, 211 (1958)>
    =1958ApJS....3..211A
     Corwin Jr. H.G.
    <Astron. J. 79, 1356 (1974)>
    =1974AJ.....79.1356C
     Zwicky F., Herzog E., Wild P., Karpowicz M., Kowal C.T.
    <Catalogue of galaxies and of clusters of galaxies,
     California Institute of Technology, Pasadena, 6 vols.(1961-68>
    =1961CGCG..C......0Z
================================================================================
ADC_Keywords: Clusters, galaxy

Description:
   The catalog was originally prepared at the Bulgarian Academy of Sciences.
   The Abell clusters are rich, compact clusters of galaxies identified by
   Abell (1958).  These clusters were identified on the red plates of the
   Palomar Observatory Sky Survey (POSS).  The Zwicky clusters were identified
   by Zwicky et al.  (1961-68) in 506 POSS fields.  They are rich clusters,
   each having at least 50 members within 3 mag of the brightest
   member.  The catalog includes cluster identification, several coordinate
   systems, magnitude of the tenth brightest cluster member, distance groups,
   richness groups, size, mean apparent population, and distance.

File Summary:
--------------------------------------------------------------------------------
 FileName    Lrecl    Records    Explanations
--------------------------------------------------------------------------------
ReadMe          80          .    This file
adc.doc         80        614    Documentation written by Robert S. Hill
abell.dat      130       2712    Abell Clusters (Abell, 1958; Corwin, 1974)
zwicky.dat     130       9134    Zwicky Clusters (Zwicky et al., 1961-68)
zwindex.dat    130       9134    Zwicky Clusters index
--------------------------------------------------------------------------------

Byte-by-byte Description of file: abell.dat
--------------------------------------------------------------------------------
   Bytes Format  Units   Label     Explanations
--------------------------------------------------------------------------------
   2-  5  I4     ---     Abell     Abell cluster number
       7  I1     ---     n_Abell   [1/2] '2' if in Abell's statistical sample,
                                         '1' if not
   9- 10  I2     h       RAh       Hours RA, 1950.0
  12- 15  F4.1   min     RAm       Minutes RA, 1950.0
      17  A1     ---     DE-       Sign Dec, 1950.0
  18- 19  I2     deg     DEd       Degrees Dec, 1950.0
  21- 22  I2     arcmin  DEm       Minutes Dec, 1950.0
  25- 28  F4.1   mag     Mag10     Magnitude of 10th brightest cluster member
      31  I1     ---     DistGroup [0/7] Distance group (1)
      34  I1     ---     RichGroup [0/5] Richness group (2)
  37- 42  F6.2   deg     GLON      Galactic longitude
  44- 49  F6.2   deg     GLAT      Galactic latitude
  52- 58  F7.4   ---     RLamb     Lambert distance from pole (3)
  60- 66  F7.4   ---     XLamb     Lambert X coordinate (3)
  68- 74  F7.4   ---     YLamb     Lambert Y coordinate (3)
  77- 82  F6.2   deg     SGLON     Supergalactic longitude (de Vaucouleur's
                                     system)
  84- 89  F6.2   deg     SGLAT     Supergalactic latitude
  92- 95  F4.2   deg     ClusRad   Corrected Abell cluster radius
  98-103  F6.3   deg2    ClusArea  Cluster area computed from ClusRad
 106-109  I4     ct/deg2 Pop       Mean apparent population (galaxies/sq.deg)
 112-114  I3     Mpc     Dist      Radial distance to cluster
 117-120  I4     Mpc     DistX     X component of Distance
 122-125  I4     Mpc     DistY     Y component of Distance
 127-130  I4     Mpc     DistZ     Z component of Distance
--------------------------------------------------------------------------------
Note (1): DistGroup is Based on the magnitude of the 10th brightest member;
   it is defined as follows:
   '0'= < 13.3                  '4'= 15.7 - 16.4
   '1'= 13.3 - 14.0             '5'= 16.5 - 17.2
   '2'= 14.1 - 14.8             '6'= 17.3 - 18.0
   '3'= 14.9 - 15.6             '7'= > 18.0
Note (2): RichGroup depends on galaxy counts as follows:
   '0'= 30 - 40                 '3'= 130 - 199
   '1'= 50 - 79                 '4'= 200 - 299
   '2'= 80 - 129                '5'= 300 or over.
Note (3): The Lambert projection is an equal-area projection, where the
    distance to the center (nearest galactic pole) RLamb is defined by:
        RLamb = 2 sin (theta/2)     where theta = polar distance = (90-b)
    and the position angle is the longitude.
    RLamb is negative for clusters located in southern galactic hemisphere.
    The Cartesian values XLamb and YLamb are defined by:
        XLamb = RLamb sin(l)        (component directed toward l=90deg)
        YLamb = RLamb cos(l)        (component directed toward l=0deg)
    RLamb, XLamb and YLamb are therefore in range [-sqrt(2), +sqrt(2)]
--------------------------------------------------------------------------------

Byte-by-byte Description of file: zwicky.dat
--------------------------------------------------------------------------------
   Bytes Format  Units   Label     Explanations
--------------------------------------------------------------------------------
   2-  5  I4     ---     Zwicky    Zwicky cluster number
   8-  9  I2     h       RAh       Hours RA, 1950.0
  11- 14  F4.1   min     RAm       Minutes RA, 1950.0
      17  A1     ---     DE-       Sign Dec, 1950.0
  18- 19  I2     deg     DEd       Degrees Dec, 1950.0
  21- 22  I2     arcmin  DEm       Minutes Dec, 1950.0
      26  I1     ---     Type      [1/3] Cluster type (1)
  30- 33  I4     ---     GalCnt    Population of cluster (number of galaxies)
  37- 40  F4.1   cm      Diam      Diameter of cluster
      44  I1     ---     DistGroup Distance group (2)
  48- 53  F6.2   deg     GLON      Galactic longitude
  56- 61  F6.2   deg     GLAT      Galactic latitude
  65- 71  F7.4   ---     RLamb     Lambert distance from pole (3)
  74- 80  F7.4   ---     XLamb     Lambert X coordinate (3)
  83- 89  F7.4   ---     YLamb     Lambert Y coordinate (3)
  93- 98  F6.2   deg     SGLON     Supergalactic longitude, de Vaucouleur's
                                     system
 101-106  F6.2   deg     SGLAT     Supergalactic latitude
 110-113  F4.2   deg     ClusRad   Cluster radius: 0.09326 * Diam
 116-122  F7.3   deg2    ClusArea  Cluster area: 0.02733 * Diam**2
 126-130  I5     ct/deg2 Pop       Mean apparent population (galaxies/sq.deg)
--------------------------------------------------------------------------------
Note (1): Cluster type is '1'=open; '2'=medium compact; '3'=compact
Note (2): DistGroup is:
        '1'= near               '4'= very distant
        '2'= medium distant     '5'= extremely distant
        '3'= distant
Note (3): Lambert projection is explained above in Note(3) of file: abell.dat.
--------------------------------------------------------------------------------

Byte-by-byte Description of file: zwindex.dat
--------------------------------------------------------------------------------
   Bytes Format  Units   Label    Explanations
--------------------------------------------------------------------------------
   2-  5  I4     ---     Zwicky   Zwicky cluster number
   8-  9  I2     h       RAh      Hours RA, 1950.0
  11- 14  F4.1   min     RAm      Minutes RA, 1950.0
      17  A1     ---     DE-      Sign Dec, 1950.0
  18- 19  I2     deg     DEd      Degrees Dec, 1950.0
  21- 22  I2     arcmin  DEm      Minutes Dec, 1950.0
  25- 27  I3     ---     Area1    [1/559]? Plate area containing cluster (1)
  29- 31  I3     ---     Number1  [1/120]? Cluster number within plate area (1)
  34- 36  I3     ---     Area2    [1/559]? Plate area containing cluster (1)
  38- 40  I3     ---     Number2  [1/120]? Cluster number within plate area (1)
  43- 45  I3     ---     Area3    [1/559]? Plate area containing cluster (1)
  47- 49  I3     ---     Number3  [1/120]? Cluster number within plate area (1)
  52- 54  I3     ---     Area4    [1/559]? Plate area containing cluster (1)
  56- 58  I3     ---     Number4  [1/120]? Cluster number within plate area (1)
  61- 63  I3     ---     Area5    [1/559]? Plate area containing cluster (1)
  65- 67  I3     ---     Number5  [1/120]? Cluster number within plate area (1)
  70- 72  I3     ---     Area6    [1/559]? Plate area containing cluster (1)
  74- 76  I3     ---     Number6  [1/120]? Cluster number within plate area (1)
  79- 81  I3     ---     Area7    [1/559]? Plate area containing cluster (1)
  83- 85  I3     ---     Number7  [1/120]? Cluster number within plate area (1)
  88- 90  I3     ---     Area8    [1/559]? Plate area containing cluster (1)
  92- 94  I3     ---     Number8  [1/120]? Cluster number within plate area (1)
  97- 99  I3     ---     Area9    [1/559]? Plate area containing cluster (1)
 101-103  I3     ---     Number9  [1/120]? Cluster number within plate area (1)
 106-108  I3     ---     Area10   [1/559]? Plate area containing cluster (1)
 110-112  I3     ---     Number10 [1/120]? Cluster number within plate area (1)
 115-117  I3     ---     Area11   [1/559]? Plate area containing cluster (1)
 119-121  I3     ---     Number11 [1/120]? Cluster number within plate area (1)
 124-126  I3     ---     Area12   [1/559]? Plate area containing cluster (1)
 128-130  I3     ---     Number12 [1/120]? Cluster number within plate area (1)
--------------------------------------------------------------------------------
Note (1):
    Up to 12 Zwicky plate numbers and cluster numbers within the plates
    (a cluster often spreads into several plate areas). Pairs are sorted
    in order of increasing order of plate-area number.

Historical Notes:
  * The catalogue has been prepared initially by the Bulgarian Academy of
    Sciences
  * See in "adc.doc" file, section 4, from the
    "Selected Astronomical Catalogs" Vol. 1 CD-ROM (1992), directory:
    /cd6/nonstell/galaxies/abzwclus
================================================================================
(End)                                    Francois Ochsenbein [CDS]   12-Apr-1995

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