Contribution from Ultrahigh-Energy Cosmic Rays to the Extragalactic Diffuse Gamma Ray Emission

Abstract

The diffuse gamma ray emission produced by ultrahigh-energy cosmic rays (E > 4 × 10¹⁹ eV) in intergalactic space is discussed. Particles with monoenergetic or hard injection spectra, formed probably upon the acceleration of particles in supermassive black holes, are considered. It is found that intensity of the diffuse gamma ray emission depends on the shape of the injection spectrum. It is therefore concluded that data on intergalactic gamma ray emission can be used to investigate supermassive black holes.