The properties of GRB with high energy emission

The properties of GRB with presence of high energy emission within RHESSI and SWIFT t90 intervals in spectra are discussed. High energy component was first registered by COMPTEL and EGRET onboard CGRO. The shape of energy spectra of GRB with presence of high energy emission can follows the Band model up to some tens or hundreds of MeV (as for GRB021008) or contain additional power law component (for example, GRB050525B and GRB 090902B). The analysis of energy spectra of GRB with presence additional component shown that the bend was in energy region 2-10 MeV. The results of analysis of GRB with presence high energy emission reveal that temporal profiles of part of events similar in various energy bands in prompt phase (as for GRB080528, GRB021008) but during some such GRB extended high energy emission was detected (for example, GRB 090902B). And for other part of GRB temporal profiles are quite different in various energy bands in prompt phase (as for GRB050525B), but during some such events extended high energy emission was observed too -for example, GRB080514B. Moreover, high energy precursors were registered during several GRB -some photons in energy band 30 MeV -30 GeV were detected by AGILE during GRB080514B.