Clustering around radio galaxies at z~1.5
Abstract
The importance of studying old elliptical galaxies at redshift z ~ 1.5 is reviewed, considering both what can be learned by extending studies of the evolution of cluster galaxy scaling relations to earlier cosmic epochs, and the age-dating of old elliptical galaxies at high redshifts. Following this, the first results are provided of an on-going project to find such distant elliptical galaxies, through an investigation of the cluster environments of powerful radio sources with redshifts 1.44 < z < 1.7. These studies show a considerable excess of red galaxies in the radio sources fields, with the magnitudes (K >~ 17.5) and colours (R-K > 4) expected of old passively evolving galaxies at the radio source redshift. The red galaxy overdensities are found on two different scales around the radio sources; a pronounced small-scale peak at radial distances of <~ 150 kpc, and a weaker large-scale excess extending out to 1 - 1.5 Mpc. The presence and richness of these red galaxy excesses varies considerably from source to source. An interpretation of these results is provided.
Keywords
Cite
@article{arxiv.astro-ph/0212160,
title = {Clustering around radio galaxies at z~1.5},
author = {P. N. Best},
journal= {arXiv preprint arXiv:astro-ph/0212160},
year = {2009}
}
Comments
LaTeX, 6 pages, Elsevier Science format. To appear in "Radio galaxies: past, present & future". eds. M. Jarvis et al., Leiden, Nov 2002