Stott, J.P. and Smail, I. and Edge, A.C. and Ebeling, H. and Smith, G.P. and Kneib, J.-P. and Pimbblet, K.A. (2007) 'An increase in the faint red galaxy population in massive clusters since z \~ 0.5.', Astrophysical journal., 661 (1). pp. 95-101.
We compare the luminosity functions for red galaxies lying on the rest-frame (U - V) color-magnitude sequence in a homogeneous sample of 10 X-ray-luminous clusters from the MACS survey at z ~ 0.5 to a similarly selected X-ray cluster sample at z ~ 0.1. We exploit deep Hubble Space Telescope ACS imaging in the F555W and F814W passbands of the central 1.2 Mpc diameter regions of the distant clusters to measure precise colors for the galaxies in these regions and statistically correct for contamination by field galaxies using observations of blank fields. We apply an identical analysis to ground-based photometry of the z ~ 0.1 sample. This comparison demonstrates that the number of faint, MV ~ -19, red galaxies relative to the bright population seen in the central regions of massive clusters has roughly doubled over the 4 Gyr between z ~ 0.5 and z ~ 0.1. We quantify this difference by measuring the dwarf-giant ratio on the red sequence, which increases by a factor of at least 2.2 ± 0.4 since z ~ 0.5. This is consistent with the idea that many faint, blue, star-forming galaxies in high-density environments are transforming onto the red sequence in the last half of the Hubble time.
|Keywords:||Galaxies, Clusters, Evolution, Luminosity function, Mass function.|
|Full text:||(VoR) Version of Record|
Download PDF (557Kb)
|Publisher Web site:||http://dx.doi.org/10.1086/514329|
|Publisher statement:||© 2007. The American Astronomical Society. All rights reserved. Printed in the U.S.A.|
|Date accepted:||No date available|
|Date deposited:||04 September 2013|
|Date of first online publication:||May 2007|
|Date first made open access:||No date available|
Save or Share this output
|Look up in GoogleScholar|