ACDS V10.0 - Detailed Description of VII/259

ACDS V10.0 - Fri Jan 17 08:34:12 CET 2025

| # Detailed Description of VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009) |

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/259             6dF  galaxy survey final redshift release   (Jones+, 2009)
    ================================================================================
    6dF galaxy survey final redshift release
        Jones D.H., Read M.A., Saunders W., Colless M., Jarrett T., Parker Q.A.,
        Fairall A.P., Mauch T., Sadler E.M., Watson F.G., Burton D., Campbell L.A.,
        Cass P., Croom S.M., Dawe J., Fiegert K., Frankcombe L., Hartley M.,
        Huchra J., James D., Kirby E., Lahav O., Lucey J., Mamon G.A., Moore L.,
        Peterson B.A., Prior S., Proust D., Russell K., Safouris V.,
        Wakamatsu K.-I., Westra E., Williams M.
       <Mon. Not. R. Astron. Soc. 399, 683 (2009) >
       =2009MNRAS.399..683J
    ================================================================================
    ADC_Keywords: Surveys; Galaxy catalogs; Redshifts; Galaxies, photometry

    Keywords: surveys - galaxies: distances and redshifts -
              cosmology: observations - large-scale structure of Universe

    Description:
        The final redshift release of the 6dF Galaxy Survey (6dFGS) is a
        combined redshift and peculiar velocity survey over the southern
        sky (|b|>10°). Its 136304 spectra have yielded 110256 new
        extragalactic redshifts and a new catalogue of 125071 galaxies
        making near-complete samples with limits in (K, H, J, rF, bJ)
        (12.65, 12.95, 13.75, 15.60, 16.75). The median redshift of the
        survey is 0.053.

        The catalog includes basic data for the galaxies in the 6dFGS with
        redshifts, using the best 6dFGS redshifts (Q=3 or 4) plus available
        redshifts from SDSS, 2dFGRS and ZCAT (124647 entries in all).
        It supersedes the previous DR2 version (Cat. VII/249).

        The URL of the 6dFGS data base is: http://www-wfau.roe.ac.uk/6dFGS

    File Summary:

           FileName      Lrecl  Records   Explanations

    ×                   80        .   This file
    × ReadMe            80        .   This file
    × 6dfgs.dat        178   124647   The 6dF Galaxy Survey Redshift Catalogue Data
                                Release 3 (final release)
    × spectra.dat      148   136304   Table of spectral observations

    See also:
        http://www-wfau.roe.ac.uk/6dFGS : the 6dFGS home page
        VII/193 : The CfA Redshift Catalogue, Version June 1995 (Huchra+ 1995)
        VII/250 : The 2dF Galaxy Redshift Survey (2dFGRS) (2dFGRS Team, 1998-2003)
         II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
        http://www.sdss.org : SDSS Home Page

    Byte-by-byte Description of file:  6dfgs.dat

       Bytes Format Units   Label     Explanations

       1- 15  A15   ---     6dFGS     Galaxy survey target ID (gHHMMSSs+DDMMSS)
      18- 19  I2    h       RAh       Right ascension (J2000)
      21- 22  I2    min     RAm       Right ascension (J2000)
      24- 28  F5.2  s       RAs       [0,60] Right ascension (J2000)
          31  A1    ---     DE-       Declination sign (J2000)
      32- 33  I2    deg     DEd       Declination (J2000)
      35- 36  I2    arcmin  DEm       Declination (J2000)
      38- 41  F4.1  arcsec  DEs       [0,60] Declination (J2000)
          44  I1    ---     Nm        Number of 6dFGS measurements (of any quality)
          48  I1    ---     Nz        Number of measurements used in final cz
                                       (of quality 3 or 4 only)
      50- 54  F5.2  mag     bJmag     Recalibrated bJ magnitude (BMAG)
      56- 58  I3    ---     PrID      Programme ID number (PROGID in database)
      60- 64  F5.2  mag     rFmag     Recalibrated rF magnitude (RMAG)
          67  I1    ---     S/G       [0/4] SuperCOSMOS star/galaxy classifier:
                                        1=galaxy, 2=star, 3=unclassifiable, 4=noise
      69- 70  I2    ---     f_cz      Comparison flags between z measurements (2)
      72- 78  I7    km/s    cz        Best available combined recession velocity cz
      80- 82  I3    km/s    e_cz      Combined uncertainty in cz (3)
      84- 86  I3    ---     r_cz      Code identifying source of redshift (4)
          89  I1    ---     q_cz      Best redshift quality value available (5)
      92- 97  F6.2  deg     GLON      [0,360.0] Galactic longitude
      99-104  F6.2  deg     GLAT      Galactic latitude
     106-110  F5.2  mag     AV        Galactic extinction in V magnitudes (from
                                       Schlegel et al., 1998ApJ...500..525S)
         112  I1    ---     w         Original weight source had for first round of
                                       fibre allocation
     114-119  I6    ---     Target    [2/179260] TARGETID number in 6dFGS database
     121-129  A9    ---     Template  Template code(s) (6)
     131-148  A18   ---     FileName  Name of redshift field file containing the
                                       redshift (7)
     150-178  A29   ---     SpecID    SPECID values of redshifts contributing to the
                                       final combined redshift

    Note (2): The comparison threshold is 330km/s, and the
         flag is the sum of the following individual values:
          0 = sole measurement or agreement within threshold
          1 = >=1 6dFGS-6dFGS disagreement  (median cz listed)
          2 = >=1 6dFGS-ZCAT disagreement   (6dFGS cz listed)
          4 = >=1 6dFGS-2dFGRS disagreement (6dFGS cz listed)
          8 = >=1 6dFGS-SDSS disagreement   (6dFGS cz listed)
         16 = >=1 6dFGS-ZCAT agreement      (6dFGS cz listed)
         32 = >=1 6dFGS-2dFGRS agreement    (6dFGS cz listed)
         64 = >=1 6dFGS-SDSS agreement      (6dFGS cz listed)

         The 6dFGS cz values (Q=3,4) are listed in all cases in preference to
         the external value for redshift. ZCAT/2dFGRS/SDSS values are listed
         when no Q=3,4 6dFGS cz is available. Note that in the case of three or
         more 6dFGS measurements, just because one pair of 6dFGS measurements
         disagree, the redshift may in fact be secure through the remaining
         measurements. This can be checked against items Nmeas and Ncz.
    Note (3): Obtained by error-weighting individual redshifts, where Q=3
         redshifts have uncertainty 55km/s and Q=4 have 45km/s. 6dFGS redshifts
         deemed unsuitable for extragalactic use (either because of measurement
         uncertainty or spectral classification) have had their uncertainties
         set to 0km/s. SDSS redshifts have an uncertainty of 30km/s (Abazajian
         et al., 2005AJ....129.1755A). 2dFGRS redshifts have uncertainties of
         123km/s or 89km/s for redshift Q=3 or Q=4 respectively (Colless et al.
         2001, Cat. VII/250). and col. "q_cz" below). ZCAT redshifts carry
         the uncertainties from their original surveys and so vary.
    Note (4): Sources of redshift are:
          0 = no (or unreliable 6dFGS) measure;
      1..99 = ZCAT;
        126 = 6dFGS;
        250 = SDSS;
        392 = 2dFGRS
    Note (5): Quality value as follows:
          0 = no redshift quality value available
          1 = 6dFGS or 2dFGRS, unusable measurement.
          2 = 6dFGS or 2dFGRS, possible, but doubtful redshift estimate
          3 = 6dFGS or 2dFGRS, 'probable' redshift (notionally 90% confidence)
          4 = 6dFGS or 2dFGRS, reliable redshift (notionally 99% confidence)
          6 = 6dFGS confirmed Galactic source
          9 = SDSS and ZCAT sources (not a measure of quality)

         See Jones et al. (2004MNRAS.355..747J) or Colless et al. (2001, Cat.
         VII/250, 2001MNRAS.328.1039C) for details on the quality schemes used
         by 6dFGS and 2dFGRS respectively).
    Note (6): 6dFGS template if number, Z for ZCAT redshift, T for 2dFGRS,
         S for SDSS, or 0 if not available. 6dFGS template number (KBESTR)
         is 1 or 2 for early-type galaxy, 3, 4 or 5 for late-type galaxies.
    Note (7): Name of redshift field file if sourced from 6dFGS; or the words
         2dFGRS, ZCAT, or SDSS if the redshift is from those surveys; otherwise
         "not_available" if the field information is not available, for
         whatever reason.

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

       Bytes Format Units   Label     Explanations

       1-  6  I6    ---     SpecID    Unique ID number used for spectrum image
       8- 13  I6    ---     Target    [1/500528] TARGETID number in 6dFGS database
      15- 29  A15   ---     6dFGS     Matching name in target table, used to name
                                       FITS files and generate thumbnail images
      31- 32  I2    h       RAh       Observed right ascension (J2000)
          33  A1    ---     ---       [:]
      34- 35  I2    min     RAm       Observed right ascension (J2000)
          36  A1    ---     ---       [:]
      37- 41  F5.2  s       RAs       [0/60] Observed right ascension (J2000)
          43  A1    ---     DE-       Observed Declination sign (J2000)
      44- 45  I2    deg     DEd       Observed Declination (J2000)
          46  A1    ---     ---       [:]
      47- 48  I2    arcmin  DEm       Observed Declination (J2000)
          49  A1    ---     ---       [:]
      50- 53  F4.1  arcsec  DEs       [0/60] Observed Declination (J2000)
      55- 60  F6.3  arcsec  dr        ?=-9.99 Position match error (arcsec)
      63- 70  F8.5  ---     zraw      ?=-9.999 Raw measured redshift
      72- 79  F8.5  ---     z         ?=-9.999 Heliocentric redshift
          81  I1    ---     q_z       [0/6] Redshift measurement quality:
                                            4=good to 1=bad (6=star)
      83- 88  F6.2  ---     Rcor      ?=-9.99 Cross-correlation peak
      91- 94  I4    s       ExpV      V reference frame exposure time seconds
      96-103  F8.2  d       MJD.V     ?=0 MJD of observation in V band
     106-109  I4    s       ExpR      R reference frame exposure time seconds
     111-118  F8.2  d       MJD.R     ?=0 MJD of observation in R band
     120-148  A29   ---     Com       Comments on redshift

    History:
        Copied at http://www-wfau.roe.ac.uk/6dFGS/download.html
    ================================================================================
    (End)                                      Patricia Vannier [CDS]    23-Feb-2010