ORIGIN OF THE HIGH ENERGY EXTRAGALACTIC DIFFUSE GAMMA RAY BACKGROUND

Abstract

We show that cosmic rays in external galaxies, groups and clusters rich in gas, with an average flux similar to that observed in the Milky Way, could have produced the observed extragalactic diffuse gamma radiation.

9 pages, latex, 1 faxable figure available upon request from [email protected]. Submitted to Phys Rev Lett.