Modeling the Color Magnitude Relation for Galaxy Clusters
  We investigate the origin of the colour-magnitude relation (CMR) observed in cluster galaxies by using a combination of a cosmological N-body simulation of a cluster of galaxies and a semi-analytic model of galaxy formation. The departure of galaxies in the bright end of the CMR with respect to the trend denoted by less luminous galaxies could be explained by the influence of minor mergers 
Noelia Jimenez, Sofia A. Cora, Analia Smith Castelli, and Lilia P.   Bassino
astro-ph.CO