ACDS V10.0 - Wed Apr 17 23:04:58 CEST 2019
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Detailed Description of VII/259 :
6dF galaxy survey final redshift release (Jones+, 2009)
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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)
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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
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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
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(End) Patricia Vannier [CDS] 23-Feb-2010