Evolution of Cluster Early-Type Galaxies
Abstract
The slow evolution of the M/L ratios, colors, and line strengths of cluster early-type galaxies to z=1 suggests that their stars were formed at very high redshift. At the same time, morphological studies of distant clusters indicate significant evolution in the early-type galaxy population. Striking evidence for strong morphological evolution in clusters is the discovery of a large number of red merger systems in the cluster MS 1054-03 at z=0.83. The presence of these mergers is qualitatively consistent with predictions from hierarchical galaxy formation models, and is direct evidence against an early collapse for all early-type galaxies. In most of the mergers there is no evidence for strong star formation. Therefore the mean stellar ages of the merger products will be much older than the ``assembly age'', and do not violate the constraints on the star formation epoch of early-type galaxies imposed by the color-magnitude relation and the Fundamental Plane.
Cite
@article{arxiv.astro-ph/0012090,
title = {Evolution of Cluster Early-Type Galaxies},
author = {P. G. van Dokkum and M. Franx and D. D. Kelson and G. D. Illingworth and D. Fabricant},
journal= {arXiv preprint arXiv:astro-ph/0012090},
year = {2007}
}
Comments
6 pages, 4 figures. To appear in proceedings of "Deep Fields" meeting (Garching, October 2000)