Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/221594

Title

Evolution of group galaxies from the first red-sequence cluster survey

Author(s)

Li, I. H.;  Yee, H. K. C.;  Hsieh, B. C.;  Gladders, M.

Abstract

We study the evolution of the red-galaxy fraction (f red) 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 f red than those at higher redshifts, showing a group Butcher-Oemler effect. We investigate the evolution of f red 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 (r grp), and local galaxy density (Σ5). We find that M * is the dominant parameter such that there is a strong correlation between f red and galaxy stellar mass. Furthermore, the dependence of f red on the environmental parameters is also a strong function of M *. Massive galaxies (M * 1011 M & 9737;) show little dependence of f red on r grp, M *, grp, and Σ5 over the redshift range. The dependence of f red on these parameters is primarily seen for galaxies with lower masses, especially for M * 1010.6 M ☉. We observe an apparent "group down-sizing" effect, in that galaxies in lower-mass halos, after controlling for galaxy stellar mass, have lower f red. We find a dependence of f red on both r grp and Σ5 after the other parameters are controlled. At a fixed r grp, there is a significant dependence of f red on & 0931;5, while r grp gradients of f red are seen for galaxies in similar Σ5 regions. This indicates that galaxy group environment has a residual effect over that of local galaxy density (or vice versa), and both parameters need to be considered. This result suggests that processes identified with local galaxy density, such as galaxy harassment and mergers, and those associated with accretion into a larger group halo, such as ram pressure and strangulation, are both partaking in driving galaxies to their final red quiescent state. We discuss these results in the context of the "nature versus nurture" scenario of galaxy evolution.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Information and Communication Technologies. Centre for Astrophysics and Supercomputing

Source

Astrophysical Journal, Vol. 749, no. 2 (Mar 2012), article no. 150

Publication year

2012

FOR Code(s)

0201 Astronomical and Space Sciences;  0305 Organic Chemistry;  0306 Physical Chemistry (Incl. Structural)

Keyword(s)

Galaxy clusters;  Galaxy evolution;  Photometry

Publisher

Institute of Physics Publishing

ISSN

0004-637X

Publisher URL

http://dx.doi.org/10.1088/0004-637x/749/2/150

Copyright

Copyright © 2012 The American Astronomical Society. All rights reserved. The American Astronomical Society does not allow Swinburne Research Bank to archive either the accepted manuscript or the published version of the article. However you can find an earlier version of the full text here: http://arxiv.org/abs/1202.4767.

Peer reviewed