GAMMA-400 Gamma-Ray Observations in the GeV and TeV Energy Range

The future space-based GAMMA-400 -ray telescope will operate onboard the Russian astrophysical observatory in a highly elliptic orbit during 7 years. Observing -ray sources from Galactic plane, -ray bursts, -ray diffuse emission, rays from the Sun, and rays from dark matter particles will be performed uninterruptedly for a long time ( 100 days) in point-source mode in contrast to scanning mode for Fermi-LAT and other space- and ground-based instruments. GAMMA-400 will measure rays in the energy range from 20 MeV to several TeV units, have the unprecedented angular ( at GeV) and energy ( at GeV) resolutions better than for Fermi-LAT, as well as ground-based -ray facilities, by a factor of 5–10, and perfectly separate rays from cosmic-ray background.