ACDS V10.0 - Detailed Description of VII/213

ACDS V10.0 - Sat Jan 18 01:34:58 CET 2025

| # Detailed Description of VII/213 : Hickson's Compact groups of Galaxies (Hickson+ 1982-1994) |

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.

    VII/213             Hickson's Compact groups of Galaxies   (Hickson+ 1982-1994)
    ================================================================================
    Systematic Properties of Compact Groups of Galaxies
         Hickson P.
        <Astrophys. J. 255, 382 + Erratum 259, 930 (1982)>
        =1982ApJ...255..382H
    A photometric catalog of compact groups of galaxies.
         Hickson P., Kindl E., Auman J.R.
        <Astrophys. J. Suppl. Ser. 70, 687 (1989)>
        =1989ApJS...70..687H
    The luminosity function of compact groups of galaxies
         Mendes de Oliveira C., Hickson P.
        <Astrophys. J. 380, 30 (1991)>
        =1991ApJ...380...30M
    Dynamical properties of compact groups of galaxies.
         Hickson P., Mendes de Oliveira C., Huchra J.P., Palumbo G.G.C.
        <Astrophys. J. 399, 353 (1992)>
        =1992ApJ...399..353H
    Morphology of galaxies in compact groups.
         Mendes de Oliveira C., Hickson P.
        <Astrophys. J., 427, 684 (1994)>
        =1994ApJ...427..684M
    ================================================================================
    ADC_Keywords:  Clusters, galaxy ; Galaxies, optical ; Redshifts ;
                   Galaxies, photometry ; Velocity dispersion

    Description:
        The catalog of groups (file "groups.dat") is a list of 100 compact
        groups of galaxies identified by a systematic search of the Palomar
        Observatory Sky Survey red prints. Each group contains four or more
        galaxies, has an estimated mean surface brightness brighter than 26.0
        magnitude per arcsec2 and satisfies an isolation criterion.
        Dynamical parameters were derived for 92 of the 100 groups, which are
        listed in file "dynamics.dat"; the Hubble constant was assumed to be
        Ho=100km/s/Mpc.

        Data about individual galaxies in these groups are merged into the
        "galaxies.dat" file; these data include photometric parameters,
        morphology, redshifts and absolute magnitudes originally published in
        four different papers. They result from CCD observations at CFHT
        (Canada-France-Hawaii Telescope) in 1983-1985. Redshifts were
        observed at the 1.5m telescope of the F.L. Whipple Observatory on
        Mt. Hopkins, Arizona, over the period 1984-1986, in wavelength range
        470-710nm; the remaining fainter galaxies were observed with the CFHT.

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × groups.dat        72      100   Catalog of groups (1982 paper, and errata)
    × dynamics.dat      94       92   Dynamical properties (1992 paper, table3)
    × galaxies.dat     130      463   Photometric and Velocity data for galaxies
                                    (combined tables from 1989 and 1992 papers)
    × morpho.dat        92      210   Morphology (1994 paper, table2)

    See also:
        J/A+AS/117/39 : Far-IR properties of Hickson Compact Groups (Allam+, 1996)
        J/A+A/325/473 : HCG HI-deficiency (Huchtmeier 1997)
        J/AJ/123/2976 : The UZC-SSRS2 group catalog (Ramella+, 2002)

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

       Bytes Format  Units   Label    Explanations

       1-  3  I3     ---     HCG      [1/100]+ Number of the group in this catalog
       5-  6  I2     h       RAh      Right Ascension 1950 hours
       7-  8  I2     min     RAm      Right Ascension minutes
       9- 10  I2     s       RAs      Right Ascension seconds
          11  A1     ---     DE-      Declination sign
      12- 13  I2     deg     DEd      Declination degrees (1950)
      14- 15  I2     arcmin  DEm      Declination arcminutes
      16- 17  I2     arcsec  DEs      [0,60] Declination arcseconds
          18  A1     ---     Dyna     [*] '*' when group has dynamical parameters
      20- 21  A2     ---     Type     Group type (1)
      22- 23  I2     ---     MCount   Member count (2)
      24- 28  F5.1   arcmin  AngSize  Angular size (3)
      29- 33  F5.1   mag     Totmag   Total magnitude of group (4)
      34- 38  F5.1   mag     Emag     Brightest member magnitude (5)
      39- 44  F6.3   ---     z        ? Redshift (6)
      46- 51  A6     ---     Aname1   Alternate name 1 (7)
      53- 58  A6     ---     Aname2   Alternate name 2 (7)
      60- 65  A6     ---     Aname3   Alternate name 3 (7)
      67- 72  A6     ---     Aname4   Alternate name 4 (7)

    Note (1): Two-character code (a letter followed by a number)
       classifying the group according to its two brightest members:
          S    The brightest galaxy is a spiral galaxy.
          E    The brightest galaxy is not a spiral galaxy.
          1    m(b) - m(a) >= 1.0
          2    0.5 <= m(b) - m(a) < 1.0
          3    m(b) - m(a) < 0.5
          where m(a) and m(b) are the estimated red magnitudes of the brightest
          and second brightest members, respectively, of the cluster.
    Note (2): Number of galaxies in the group. Only those galaxies within three
       magnitudes of the brightest galaxy are counted as members.
    Note (3): Angular diameter, in arcminutes, of the smallest circle containing the
       geometric centers of all group members.
    Note (4): Total estimated red magnitude of those galaxies counted as group
       members (see member count, above.)
    Note (5): Estimated red magnitude of the brightest galaxy in the group, in units
       of magnitude.
    Note (6): Corrected redshift of the brightest galaxy. In all but ten cases this
       field is blank; prefer the group redshift supplied in the file
       "dynamics.dat".
    Note (7): Other designations of the group, if any (at most, four).

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

       Bytes Format Units   Label     Explanations

       1-  3  I3    ---     HCG       [1/100]+= Group number
       6- 11  F6.4  ---     z         Group Redshift derived from the median
                                            galaxy heliocentric velocity
          14  I1    ---     n         Number of galaxies with accordant velocities
      17- 20  F4.2  [km/s]  log(sV)   Radial velocity dispersion
      22- 26  F5.2  [km/s]  log(V)    ? Estimated instrinsic 3D velocity dispersion
      28- 32  F5.2  [kpc]   log(R)    Median projected separation
      35- 39  F5.2  ---   log(Ho.tc)  Crossing time (expressed in 1/Ho units)
      42- 46  F5.2  [g]     log(Mv)   ? Virial mass of group in log. scale
      49- 53  F5.2  [g]     log(Mp)   ? Projected mass
      56- 60  F5.2  [g]     log(Ma)   ? Average mass
      63- 67  F5.2  [g]     log(Mm)   ? Median mass
      70- 74  F5.2  [g]     log(M)    ? Adopted mass
      77- 81  F5.2  [W]     log(L)    Total blue luminosity
                                        of the accordant galaxies
      83- 87  F5.2  [Sun]   log(M/L)  ? Mass-to-light ratio
      89- 94  F6.2  [g/cm3] log(rho)  ? Mass density

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

       Bytes Format Units   Label   Explanations

       1-  3  I3    ---     HCG     [1/100]+= Hickson Group number (groups.dat)
           4  A1    ---     m_HCG   [a-i]! Galaxy in HCG group
       6-  7  I2    h       RAh     Right Ascension B1950 (hours)
       8-  9  I2    min     RAm     Right Ascension B1950 (minutes)
      10- 14  F5.2  s       RAs     Right Ascension B1950 (seconds)
          15  A1    ---     DE-     Declination B1950 (sign)
      16- 17  I2    deg     DEd     Declination B1950 (degrees)
      18- 19  I2    arcmin  DEm     Declination B1950 (minutes)
      20- 23  F4.1  arcsec  DEs     Declination B1950 (seconds)
      25- 29  F5.1  arcsec  a       Semi-major axis at 25.0mag/arcsec2 isophote
      31- 34  F4.1  arcsec  b       Semi-minor axis at 25.0mag/arcsec2 isophote
      37- 40  A4    ---     MType   Hubble Morphological type
      42- 43  I2    ---     T       Numeric morphological type (1)
          44  A1    ---     morph   [m] when more morphology in file "morpho.dat"
      45- 49  I5    km/s    RVhel   ? Heliocentric velocity
      51- 53  I3    km/s   e_RVhel  ? Estimated rms in RVhel
          55  I1    ---    q_RVhel  [0/2]?  Confidence code on RVhel (2)
      57- 61  F5.2  mag     Bmag    B magnitude within 24.5mag/arcsec2 isophote
          63  I1    ---     q_Bmag  [0/5] Confidence level for Bmag (3)
      65- 69  F5.1  arcsec  DBmag   Diameter of B=24.5mag/arcsec2 isophote (4)
      71- 75  F5.2  mag     Rmag    R magnitude within 24.0mag/arcsec2 isophote
          77  I1    ---     q_Rmag  [0/5] Confidence level for Rmag (3)
      79- 83  F5.1  ---     DRmag   Diameter of R=24.0mag/arcsec2 isophote (4)
      85- 88  F4.2  mag     B-R     Colour within the 24.5mag/arcsec2 isophote
      90- 94  F5.2  mag     BTmag   BT asymptotic magnitude
      96-100  F5.2  mag     BTc     BT asymptotic magnitude corrected for
                                            internal and external extinction
     102-105  F4.2  mag    e_BTmag  Mean error on BTmag
     107-111  F5.1  mag MB-5log(h)  ? Absolute magnitude of individual galaxies,
                                        h=Ho/100, Ho=Hubble constant
     113-130  A18   ---     Names   Other names

    Note (1): the morphological type codes are:
        ---------------------------
        Hubble      Code     RC2
        ---------------------------
        E0-E7        0       -4, -5
        S0, SB0      1       -2
        S0a, SB0a    2        0
        Sa, SBa      3        1
        Sab, SBab    4        2
        Sb, SBb      5        3
        Sbc, SBbc    6        4
        Sc, SBc      7        5
        Scd, SBcd    8        6
        Sd, SBd      9        7
        Sdm, SBdm   10        8
        Sm, SDm     11        9
        Im, IBm     12       10
        cI          13       11
        ---------------------------
    Note (2): the confidence code is as follows:
         0 = highest confidence: spectral features clearly visible
         1 = lower confidence: spectral features not clearly visible
         2 = lowest confidence: very noisy spectra with no obvious features.
             Only 3 galaxies have q_RVhel=2.
    Note (3): confidence levels are as follows:
         0 = good
         1 = uncertain due to overlapping isophotes
         2 = uncertain due to contamination
         3 = uncertain due to poor calibration
         4 = uncertain due to clouds
         5 = value for HCG 64c unexplained
    Note (4): the diameter is defined as  sqrt(Area/{pi})

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

       Bytes Format Units   Label     Explanations

       1-  3  I3    ---     HCG       [1/100]+= Hickson Group number (groups.dat)
           4  A1    ---     m_HCG     [a-i]! Galaxy in HCG group
       8- 12  I5    km/s    RVhel     ? Heliocentric velocity
      16- 19  A4    ---     MType     Morphological type
      24- 92  A69   ---     Comments  Comments (1)

    Note (1): Abbreviations used in comments:
            [string 'ansac' in 58a is unexplained]
      asym.    = asymmetric
      emission = galaxy with emission lines in its nuclear spectrum
      IR       = infrared emitter (Hickson et al. 1989ApJ...341..679H,
                 Sulentic & de Mello Rabaca 1993ApJ...410..520S)
      morpho   = morphology
      n.c.i.   = nonconcentric isophotes
      r.c.     = rotation curve
      radio    = radio-loud galaxies (Menon & Hickson 1985; Menon 1993)
      tail-like= galaxy has tail-like features
      vel.     = velocity
      WR       = galaxy exhibits Wolf-Rayet spectral features

    Remarks and Modifications:
      * History of Catalogue VII/85:
        The catalogue was originally prepared at the Centre de Donnees
        astronomiques, Strasbourg (CDS), in 1986. It was then received by the
        Astronomical Data Center (ADC), NASA Goddard Space Flight Center, in
        December 1986.

        The original tape consisted of a single text file containing the
        catalog data from Table 1 of Systematic Properties of Compact Groups
        of Galaxies, in a slightly more compact format. ADC personnel deleted
        eight blank columns from the end of each record in the file to reduce
        the record size from 80 to 72 bytes and ran a FORTRAN program to check
        the validity of each field according to its data type and value. Two
        minor typographic errors discovered in the computer-readable version
        were then corrected by referring to the published catalog. A possible
        error was also detected, but not changed, in record number 97, where
        the DEC seconds field contains a value of 60 (this value appears in
        the printed version).

        P. Hickson kindly supplied a list of errata including some corrections
        in addition to the published erratum. This list is reproduced below;
        the indicated changes have already been made to the catalog data.

           ERRATUM
            HCG      AngSize       TotMag          Emag
             14       6.7           12.1           13.0
             22       5.0           10.5           11.1
             60       2.3           13.4           14.4
             69       1.9           12.2           13.1
             82       3.1           12.2           13.1
            HCG    RAh/RAm/RAs DEd/DEm/DEs
             03     00 31 39   -07 52 07
             31     04 59 08   -04 19 42
             74     15 17 14   +21 04 27
             89     21 17 34   -04 07 17

     * Catalogue VII/213 (F. Ochsenbein, CDS, 07-Jun-1999)
       This catalogue is a merged version of:
       - VII/85 (1982ApJ...255..382H), with its ReadMe description made
         by C.-H. Joseph Lyu [Hughes STX/NASA] on 16-Oct-1995, and of:
       - 1991ApJ...380...30M (absolute magnitudes) kindly supplied by
         Claudia Mendes de Oliveira coliveira@eso.org in March 1994.
       - 1989ApJS...70..687H, 1992ApJ...399..353H and 1994ApJ...427..684M
         kindly supplied by Heinz Andernach; these tables were prepared
         via OCR and proofread by him in April 1995.

     * Two typo corrected in galaxies.dat (1737 for I737 and 14382 for I4382)
    ================================================================================
    (End)                                     Francois Ochsenbein [CDS]  07-Jun-1999