AN INVERSE COMPTON PROCESS FOR THE EXCESS DIFFUSE EUV EMISSION FROM THE VIRGO AND COMA GALAXY CLUSTERS

The excess extreme-ultraviolet (EUV) emission detected in the Virgo an d Coma clusters is explained by inverse Compton scattering of cosmic m icrowave background photons, which are scattered by the relativistic e lectrons that account for the extended radio synchrotron emission of t hese clusters. The lower limits of the average magnetic fields of thes e clusters estimated from the EUV excess are close to the equipartitio n magnetic fields derived from radio observations, indicating that the electron energies and magnetic field energies might be close to equip artition. The excess emission suggests energy reservoirs of similar to 10(61) and similar to 10(60) ergs for the Coma and Virgo clusters, re spectively.