Gamma rays from accreting black holes.

The model of spherical turbulent accretion onto black holes proposed by Meszaros (1975) is used to estimate the electric field produced by the motion of magnetized turbulence cells in the accretion flow. Electrons and protons are accelerated in this field, since the runaway condition is attained. The maximum synchrotron frequency of electrons is approximately 20 MeV independent of the mass of the hole and its accretion rate. The shape of the spectrum produced via the synchrotron and Compton mechanisms by the runaway electrons is evaluated. The results may be relevant in the interpretation of some of the gamma-ray sources recently discovered by the SAS-2 and COS-B satellites.