J/ApJ/749/150 Group galaxies in the RCS (Li+, 2012)
Evolution of group galaxies from the first red-sequence cluster survey.
Li I.H., Yee H.K.C., Hsieh B.C., Gladders M.
<Astrophys. J., 749, 150 (2012)>
=2012ApJ...749..150L 2012ApJ...749..150L
ADC_Keywords: Galaxy catalogs ; Clusters, galaxy ; Redshifts
Keywords: galaxies: clusters: general - galaxies: evolution -
galaxies: photometry
Abstract:
We study the evolution of the red-galaxy fraction (fred) in 905
galaxy groups with 0.15≤z<0.52. The galaxy groups are identified by
the "probability friends-of-friends" algorithm from the first
Red-Sequence Cluster Survey (RCS1) photometric-redshift sample. There
is a high degree of uniformity in the properties of the red sequence
of the group galaxies, indicating that the luminous red-sequence
galaxies in the groups are already in place by z∼0.5 and that they
have a formation epoch of z≳2. In general, groups at lower redshifts
exhibit larger fred than those at higher redshifts, showing a group
Butcher-Oemler effect. We investigate the evolution of fred by
examining its dependence on four parameters, one of which can be
classified as intrinsic and three of which can be classified as
environmental: galaxy stellar mass (M*), total group stellar mass
(M*,grp, a proxy for group halo mass), normalized group-centric
radius (rgrp), and local galaxy density (Σ5).
Description:
We derive our galaxy group sample from the northern patches of the
first Red-Sequence Cluster Survey (RCS1), which is an imaging survey
with the primary goal of measuring Ωm and σ8 using the
cluster mass function (Gladders & Yee 2005, Cat. J/ApJS/157/1 ;
Gladders et al. 2007ApJ...655..128G 2007ApJ...655..128G). The survey covers 22 widely
separated patches in total in the northern and southern sky with a
total area of 92deg2. The observations were carried out from 1999
May to 2001 January. The imaging in Rc and z' of the 10 northern
patches was conducted using the CFH-12K camera on the 3.6m
Canada-France-Hawaii Telescope (CFHT).
To obtain photometric redshifts, we require additional photometric
bands. The B and V photometry for the RCS1 Northern patches was
obtained as a follow-up project using the CFH-12K camera (Hsieh et al.
2005, Cat. J/ApJS/158/161). It covers 33.6deg2 in total with 108
pointings (∼75% of the original RCS1-CFHT patches). This defines the
sky area used for our group catalog. The runs were carried out from
2001 May to 2002 June.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 1153 Catalogs of Red-Sequence Cluster Survey (RCS)
galaxy groups
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See also:
J/ApJS/158/161 : Photometric redshift catalog from the RCS (Hsieh+, 2005)
J/ApJS/157/1 : Red-Sequence Cluster Survey (Gladders+, 2005)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- ID Group identification (NNNN_NNN)
11- 12 I2 h RAh Hour of Right Ascension (J2000)
14- 15 I2 min RAm Minute of Right Ascension (J2000)
17- 21 F5.2 s RAs Second of Right Ascension (J2000)
23 A1 --- DE- Sign of the Declination (J2000)
24- 25 I2 deg DEd Degree of Declination (J2000)
27- 28 I2 arcmin DEm Arcminute of Declination (J2000)
30- 34 F5.2 arcsec DEs Arcsecond of Declination (J2000)
36- 40 F5.3 --- zgrp [0.1/0.6] Group photometric redshift
42- 46 F5.3 --- e_zgrp [0.004/0.07] Uncertainty in zgrp
48- 53 F6.3 --- Ngal [5/53] Net "probability friends-of-friends"
(pFoF) member count (1)
55- 60 F6.3 [Msun] Mgrp [9/14]?=-9.99 log of total group stellar
mass (2)
62- 65 I4 --- Bgc [-216/2845] Richness parameter Bgc (3)
67- 69 I3 --- e_Bgc [133/361] Uncertainty in Bgc
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Note (1): After correcting for background contamination and completeness
weights.
Note (2): Computed using all group members within 0.5 R200 and with
background contamination corrected.
Note (3): Richness parameter defined by Longair & Seidner (1979MNRAS.189..433L 1979MNRAS.189..433L);
computed using all galaxies within 0.25 Mpc to the group centers
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 27-Nov-2013