‘‘Gamma‐gun’’ in the center of the galaxy

This paper discusses a model of physical processes that occur in the center of the Galaxy and cause the emission of the 511 keV annihilation γ‐line and of a continuous γ‐spectrum. The hypothesis of the paper is that electron positron pairs whose annihilation produces the observed γ‐line are formed when a gas‐cloud target is irradiated by a directed beam of hard (∼100 MeV) γ‐quanta. A model is developed that shows how a γ‐beam (gamma‐gun) forms near a supermassive rotating black‐hole surrounded by a gaseous accretion disk with a magnetic field. The results of numerical simulations are compared with observational data.