AAS 203rd Meeting, January 2004
Session 30 Galaxy Clusters and Large Scale Structure I
Oral, Monday, January 5, 2004, 2:00-3:30pm, Centennial I/II

## [30.06] Environmental Impact on Cluster Dwarf Galaxy Evolution

W.A. Barkhouse (Harvard-Smithsonian CfA)

The results from a comprehensive study of 71 low-redshift (0.0\leq z\leq 0.2) galaxy clusters are described. The luminosity function, dwarf-to-giant ratio, and the blue-to-red galaxy ratio are presented as a function of r200 (i.e., ~virial radius). The radial dependence of these measurements indicates that blue dwarf galaxies are tidally disrupted in the inner cluster region or fade and turn red. The red, mainly nucleated, dwarf galaxies remain relatively unchanged with respect to cluster-centric radius, while giant blue galaxies have transformed into their red galaxy counterparts. These results support the scenario that infalling field galaxies have their star formation truncated by some dynamical process and that disrupted dwarf galaxies help to form the halo of cD and Brightest Cluster Galaxies.