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 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 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:
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FileName Lrecl Records Explanations
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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
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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
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Bytes Format Units Label Explanations
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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)
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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
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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 2008MNRAS.387.1281M
Brasseur et al., Paper II 2009MNRAS.392.1141B 2009MNRAS.392.1141B
McConnachie et al., Paper III 2009MNRAS.395..255M 2009MNRAS.395..255M, Cat. J/MNRAS/395/255
(End) Patricia Vannier [CDS] 23-Jul-2012