  New radio and X-ray data are reported for the rich cluster Abell 2255. The
cluster radio emission is characterized by the presence of a diffuse halo
source, located at the cluster center, and a more peripheral ridge of radio
emission which could be a relic. In addition, 6 tailed radio sources and a
small double are found to be associated with cluster galaxies. At X-ray
wavelengths, the cluster shows elongated emission in the center, indicating an
ongoing cluster merger, with the axis in the east-west to southeast-northwest
direction. The overall cluster temperature is found from the ROSAT observation
to be kT = 3.5 +- 1.5 keV, while the temperature determined from the Einstein
MPC data was reported to be 7.3 keV. We interpret this difference as due to the
existence in the cluster of several coexisting temperature components. The
merger process can provide energy to maintain the radio halo, but we stress the
need for tailed radio galaxies orbiting at the cluster center to provide the
halo relativistic electrons.
