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SIXDFGS - 6dFGS Galaxy Survey Final Redshift Release Catalog

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Overview

The final redshift release of the 6dF Galaxy Survey (6dFGS) is a combined redshift and peculiar velocity survey over the southern sky (|b| > 10 degrees). Its 136,304 spectra have yielded 110,256 new extragalactic redshifts and a new catalogue of 125,071 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 (radial velocity quality flag Q =3 or 4) plus available redshifts from SDSS, 2dFGRS and ZCAT (124,647 entries in all). It supersedes the previous DR2 version (CDS Cat. VII/249).

The home page of of the 6dFGS database is http://www-wfau.roe.ac.uk/6dFGS.

Any use of these data should explicitly state that they come from the Final Release of 6dFGS and cite both the 6dGS DR3 paper (Jones et al. 2009, MNRAS, 399, 683) as well as the original 6dFGS survey paper (Jones et al. 2004, MNRAS, 355, 747).


Catalog Bibcode

2009MNRAS.399..683J

References

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

Provenance

This table was created by the HEASARC in March 2011 based on CDS Catalog VII/259 file 6dfgs.dat.

Parameters

Name
The CDS-recommended galaxy survey target identification for the 6dF Galaxy Survey based on its J2000 equatorial position, viz. '6dFGS gJHHMMSS.s+DDMMSS'. In the original CDS table for this catalog, the period and the 'J' for Julian were omitted.

RA
The Right Ascension of the 6dFGS galaxy in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.01 seconds of time in the original table.

Dec
The Declination of the 6dFGS galaxy in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the 6dFGS galaxy.

BII
The Galactic Latitude of the 6dFGS galaxy.

Num_Total_Measures
The number of 6dFGS radial velocity (cz) measurements (of any quality).

Num_Highq_Measure
The number of 6dFGS measurements used in the final radial velocity (of quality Q = 3 or 4 only).

BJ_Mag
The recalibrated b_J magnitude. The photometry comes from the SuperCOSMOS Catalog (Hambly et al. 2001, MNRAS, 326, 1279 and Hambly et al. 2001, MNRAS, 326, 1315), following its reclibration for the 2dFGRS (Cole et al. 2005, MNRAS, 362, 505).

Program_ID
The program identification number (called PROGID in the 6dFGS database).

Rf_Mag
The recalibrated r_F magnitude. The photometry comes from the SuperCOSMOS Catalog (Hambly et al. 2001, MNRAS, 326, 1279 and Hambly et al. 2001, MNRAS, 326, 1315), following its reclibration for the 2dFGRS (Cole et al. 2005, MNRAS, 362, 505).

Supercosmos_Class
The SuperCOSMOS star/galaxy classifier value, which can have the following meanings:

   1=Galaxy,
   2=Star,
   3=Unclassifiable,
   4=Noise.
  

Radial_Velocity_Compflag
This parameter contains information on the comparative consistency between redshift measurements, (where the comparison threshold is 33 km/sec, and the quoted value is the sum of the individual comparison flags listed below), as follows:

        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 (of quality values Q = 3 or 4) are listed in all cases in preference to the external value for redshift. ZCAT/2dFGRS/SDSS values are listed when no Q = 3 or 4 6dFGS cz is available. Note that in the case of 3 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 the num_total_measure and num_high_measure parameter values.

Radial_Velocity
The best available combined recession velocity (redshift) cz value, in km/s.

Radial_Velocity_Error
The combined uncertainty in the best available combined recession velocity (redshift) cz value, in km/sec. This is obtained by error-weighting the individual redshifts, where Q = 3 redshifts have an uncertainty of 55 km/s and Q = 4 of 45 km/s. 6dFGS redshifts deemed unsuitable for extragalactic use (either because of measurement uncertainty or spectral classification) have had their uncertainties set to 0 km/s. SDSS redshifts have an uncertainty of 30 km/s (Abazajian et al. 2005, AJ, 129, 1755). 2dFGRS redshifts have uncertainties of 123 km/s or 89 km/s for redshift qulaities 3 or 4 respectively (Colless et al. 2001, CDS Cat. <VII/250>), and the value of the radial_velocity_qualflag parameter). ZCAT redshifts bear the uncertainties from their original surveys and so vary.

Ref_Radial_Velocity
A code identifying the source of the radial velocity (redshift), as follows:

        0 = no (or unreliable 6dFGS) measure;
    1..99 = ZCAT;
      126 = 6dFGS;
      250 = SDSS;
      392 = 2dFGRS.
  

Radial_Velocity_Qualflag
The best redshift quality value Q available, coded 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. (2004, MNRAS, 355, 747) or Colless et al. (2001, CDS Cat. VII/250 = 2001, MNRAS, 328, 1039C) for details on the quality schemes used by 6dFGS and 2dFGRS respectively).

Av
The Galactic extinction towards the galaxy, in the V band, in magnitudes. This is taken from from Schlegel et al. (1998, ApJ, 500, 525).

Original_Weight
The original weight which the source had for the first round of fibre allocation.

Target_ID
The unique target identification number (between 2 and 179260) for the galaxy in the 6dFGS database.

Template_Code
This parameter contains the numerical 6dFGS template code(s), else 'Z' for ZCAT redshift, 'T' for 2dFGRS, 'S' for SDSS, or '0' if not available. The 6dFGS template number (KBESTR in the 6dFGS database) is 1 or 2 for an early-type galaxy, and 3, 4 or 5 for late-type galaxies.

Name_Redshift_Field
The name of the redshift field file ontaining the redshift, if sourced from 6dFGS, the words '2dFGRS', 'ZCAT', or 'SDSS' if the redshift is from those surveys, and otherwise 'not_available' if the field information is not available, for whatever reason.

SpecID_Values
The SPECID values of the redshifts contributing to the final combined redshift value for the galaxy. SPECID is a unique spectral ID (an integer) for 6dFGS observations, and is different for repeat observations of the same object.


Contact Person

Questions regarding the SIXDFGS database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 4-Apr-2011