Non-thermal radiation from Cygnus X-1 corona

Abstract

Cygnus X-1 was the first X-ray source widely accepted to be a black hole candidateand remains among the most studied astronomical objects in its class. The detection ofnon-thermal radio, hard X-rays and gamma rays reveals the fact that this kind of objectsare capable of accelerating particles up to very high energies.In order to explain the electromagnetic emission from Cygnus X-1 in the low-hardstate we present a model of a black hole corona with both relativistic lepton and hadroncontent. We characterize the corona as a two-temperature hot plasma plus a mixed nonthermalpopulation in which energetic particles interact with magnetic, photon and matterfields. Our calculations include the radiation emitted by secondary particles (pions,muons and electron/positron pairs). Finally, we take into account the effects of photonabsorption. We compare the results obtained from our model with data of Cygnus X-1obtained by the COMPTEL instrument.