Inverse Compton Scattering as the Source of Diffuse Extreme-Ultraviolet Emission in the Coma Cluster of Galaxies

We have examined the hypothesis that the majority of the diffuse EUV flux in the Coma Cluster is due to inverse Compton scattering of low-energy cosmic-ray electrons (0.16 < ϵ < 0.31 GeV) against the 3 K blackbody background. We present data on the two-dimensional spatial distribution of the EUV flux and show that these data provide strong support for a nonthermal origin for the EUV flux. However, we show that this emission cannot be produced by an extrapolation to lower energies of the observed synchrotron radio emitting electrons and that an additional component of low-energy cosmic-ray electrons is required.