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J/MNRAS/418/1409    Compact groups of galaxies in SDSS DR7       (Mendel+, 2011)
Compact groups in theory and practice.
IV. The connection to large-scale structure.
    Mendel J.T., Ellison S.L., Simard L., Patton D.R., McConnachie A.W.
   <Mon. Not. R. Astron. Soc., 418, 1409-1422 (2011)>
   =2011MNRAS.418.1409M
ADC_Keywords: Surveys ; Clusters, galaxy ; Morphology ; Redshifts

Keywords: galaxies: evolution - galaxies: groups: general -
          galaxies: interactions - galaxies: photometry - galaxies: structure

Abstract:
    We investigate the properties of photometrically selected compact
    groups (CGs) in the Sloan Digital Sky Survey. In this paper, the
    fourth in a series, we focus on understanding the characteristics of
    our observed CG sample with particular attention paid to quantifying
    and removing contamination from projected foreground or background
    galaxies. Based on a simple comparison of pairwise redshift
    likelihoods, we find that approximately half of CGs in the parent
    sample contain one or more projected (interloping) members; our final
    clean sample contains 4566 galaxies in 1086 CGs.

Description:
    In Paper III (Cat. J/MNRAS/395/255) we describe the photometric
    selection of CGs from the SDSS Data Release 6 (Adelman-McCarthy et
    al., 2008, Cat. II/282/), which included imaging of the entire SDSS-II
    Legacy Survey area. Since that paper, SDSS Data Release 7 (DR7;
    Abazajian et al., 2009ApJS..182..543A) has provided an additional
    ∼1200deg2 of spectroscopic data, completing spectroscopic
    observations of the SDSS-II Legacy Survey footprint. In what follows
    we use galaxy catalogues drawn from SDSS DR7 and, where available,
    supplement the CG samples in Paper III with updated spectroscopic
    information.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
tablea1.dat       60     1086   Properties of CGs initially presented in Paper III
tablea2.dat       85     4566   Individual member galaxies of the groups in tablea1


See also:
   J/MNRAS/395/255 : Compact groups of galaxies in SDSS DR6 (McConnachie+, 2009)
   J/A+A/514/A102  : SDSS DR7 groups of galaxies (Tago+, 2010)


Byte-by-byte Description of file: tablea1.dat

   Bytes Format Units  Label   Explanations

   1-  7  A7    ---    ---     [SDSSCGA]
   8- 12  I05   ---    GrID    [3/2296] Group ID in catalog "A" (G1)
  14- 15  I2    h      RAh     Right ascension (J2000) of geometric group centre
  17- 18  I2    min    RAm     Right ascension (J2000) of geometric group centre
  20- 24  F5.2  s      RAs     Right ascension (J2000) of geometric group centre
      26  A1    ---    DE-     Declination sign (J2000) of geometric group centre
  27- 28  I2    deg    DEd     Declination (J2000) of geometric group centre
  30- 31  I2    arcmin DEm     Declination (J2000) of geometric group centre
  33- 37  F5.2  arcsec DEs     Declination (J2000) of geometric group centre
  39- 43  F5.3  ---    zest    Estimated redshift of the group, determined from
                                the joint probability of group member redshifts
  45- 50  F6.4  ---    e_zest  rms uncertainty on zest, determined from the
                                1σ width of the joint redshift probability
  51- 52  I2    ---    NM09    Number of group members in the original Paper III
                               photometric group catalogue (i.e. prior to
                               cleaning)
      54  I1    ---    Nclean  Number of remaining group members after
                               application of the cleaning algorithm described
                               in Section 2.2.1.
  56- 60  F5.2  Mpc    RT10    ? Distance to the nearest rich group in the Tago
                                et al. (2010, Cat. J/A+A/514/A102) catalogue,
                                estimated following the description in
                                Section 3.1 (in h70-1Mpc)


Byte-by-byte Description of file: tablea2.dat

   Bytes Format Units   Label     Explanations

   1-  7  A7    ---     ---       [SDSSCGA]
   8- 12  I05   ---     GrID      [3/2296] Group ID (G1)
      13  A1    ---     ---       [.]
      14  I1    ---     Gal       Galaxy ID in group (G1)
  16- 33  A18   ---     objID     Galaxy object ID within the SDSS
  35- 36  I2    h       RAh       Right ascension (J2000) of the galaxy
  38- 39  I2    min     RAm       Right ascension (J2000) of the galaxy
  41- 45  F5.2  s       RAs       Right ascension (J2000 of the galaxy
      47  A1    ---     DE-       Declination sign (J2000) of the galaxy
  48- 49  I2    deg     DEd       Declination (J2000) of the galaxy
  51- 52  I2    arcmin  DEm       Declination (J2000) of the galaxy
  54- 58  F5.2  arcsec  DEs       Declination (J2000) of the galaxy
  60- 65  F6.3  ---     zsp       ? Spectroscopic redshift
  67- 72  F6.4  ---     e_zsp     ? rms uncertainty on zsp
  74- 78  F5.3  ---     zph       Photometric redshift
  80- 85  F6.4  ---     e_zph     rms uncertainty on zph


Global Notes:

Note (G1): designation in PaperIII (McConnachie et al. 2009, J/MNRAS/395/255).
     Catalogue "A" is defined as the flux-limited sample with extinction-
     corrected r-band Petrosian magnitudes in the range 14.5-18.0mag.
     Groups are assigned integer numbers, and galaxies in the group are
     assigned a decimal number which integer part represents the group ID.


History:
    From electronic version of the journal

References:
    McConnachie et al., Paper I    2008MNRAS.387.1281M
    Brasseur et al.,    Paper II   2009MNRAS.392.1141B
    McConnachie et al., Paper III  2009MNRAS.395..255M, Cat. J/MNRAS/395/255
(End)                                      Patricia Vannier [CDS]    23-Jul-2012