Revisiting brightest cluster galaxy evolution with the Las Campanas distant cluster survey

We investigate the influence of environment on brightest cluster galaxy (BCG) evolution using a sample of 63 clusters at 0.3 ≤ z ≤ 0.9 drawn primarily from the Las Campanas Distant Cluster Survey and follow-up V, I, and K′ photometry. The luminosity evolution of the entire BCG sample is not adequately described by a single evolutionary model. Using the integrated light from the cluster detection as a proxy for cluster L_x and the suggestion by Burke, Collins, & Mann, we set L_x = 2 × 10⁴⁴ ergs s^-1 to be the division between high- and low-luminosity clusters. At high redshift (z > 0.6) BCGs from low-L _x clusters are fainter, on average, than those from high-L _x clusters and are best modeled as having constant luminosity with redshift. The BCGs from high-L_x clusters are best modeled as having a stellar population that formed at large redshift (z_form > 5) and is passively evolving. However, for the entire BCG population, the observed V - I and I - K′ colors are well described by a single evolutionary model in which the stellar populations have z_form > 5 and subsequently passively evolve. We conclude that accretion is proportionally more significant for BCGs in lower mass clusters at these redshifts (a factor of 2-4 increase in mass since z ∼ l for the low-L_x systems; Aragon-Salamanca and coworkers) and that the accreted matter is in the form of systems with evolved stellar populations.