1.4GHz flux densities of Abell 2255 galaxies

This cluster is among the better nearby candidates for rich cluster-cluster merger systems, with evidence including an elongated X-ray morphology, the presence of a radio halo, and substructure present in its galaxy distribution. Our radio observations reach an rms sensitivity of ~40{mu}Jy/beam, enabling us to detect (at 5{sigma}) star formation rates as low as 1.4M_{sun}_/yr from the center of the cluster out to a radial distance of 3h^-1^_75_Mpc.

The radio data are complemented by optical imaging and a large spectroscopic database, allowing us to separate all galaxies with M_Rc_<=-20 0 into cluster members and foreground/background galaxies. The spectra are also used to associate the galaxies' radio emission with either star formation or active galactic nuclei (AGNs). We compare the resulting cluster radio galaxy population with those of 19 other nearby Abell clusters and find strong evidence for an increase in the frequency of radio galaxies in Abell 2255.