The binary-rich cluster Abell 2244

A structural, luminosity, and velocity study of the cluster Abell 2244 is presented. A2244 was selected for study from the list of Struble and Rood because of its unusually binary-rich population in an evolved cD-type cluster environment, a contradiction in terms of cluster collapse scenarios versus the formation and survival of bound pairs. In comparison with the Coma cluster, A2244 is a slightly poorer version with a suspected deficiency in the number of cluster members in the core. This evidence, combined with the high-velocity dispersion of the cluster, suggests that a low-velocity population of galaxies has been consumed by the central cD galaxy. The central cD galaxy has a single low-velocity companion deep in its envelope and cross sections of its surface-brightness profile suggest that it is in transition from a depressed central surface-brightness object to a high central concentration system, a point of contention in merger models. All but two of the binary galaxies were found to be projections with other cluster members or stars and, thus, are not in conflict with the advanced dynamical age of the cluster.