  The future space-based GAMMA-400 gamma-ray telescope will operate onboard the
Russian astrophysical observatory in a highly elliptic orbit during 7 years to
observe Galactic plane, Galactic Center, Fermi Bubbles, Crab, Vela, Cygnus X,
Geminga, Sun, and other regions and measure gamma- and cosmic-ray fluxes.
Observations will be performed in the point-source mode continuously for a long
time (~100 days). GAMMA-400 will measure gamma rays in the energy range from
~20 MeV to several TeV and cosmic-ray electrons + positrons up to several tens
TeV. GAMMA-400 instrument will have very good angle and energy resolutions,
high separation efficiency of gamma rays from cosmic-ray background, as well as
electrons + positrons from protons. The main feature of GAMMA-400 is the
unprecedented angular resolution for energies >30 GeV better than the
space-based and ground-based gamma-ray telescopes by a factor of 5-10.
GAMMA-400 observations will permit to resolve gamma rays from annihilation or
decay of dark matter particles, identify many discrete sources, clarify the
structure of extended sources, specify the data on cosmic-ray electron +
positron spectra.
