A Powerful Radio Halo in the Hottest Known Cluster of Galaxies 1 E 0657 − 56

We report the detection of a diffuse radio halo source in the hottest known cluster of galaxies 1E0657−56 (RXJ0658−5557). The radio halo has a morphology similar to the X-ray emission from the hot intracluster medium. The presence of a luminous radio halo in such a hot cluster is further evidence for a steep correlation between the radio halo power and the X-ray temperature. We favour models for the origin of radio halo sources involving a direct connection between the X-ray emitting thermal particles and the radio emitting relativistic particles. Subject headings: galaxies: clusters: individual (1E0657−56 (RXJ0658−5557)) — galaxies: intergalactic medium — cosmology: cosmic microwave background — radio continuum: general —X-rays: general — techniques: interferometric — radiation mechanisms – 2 –