High energy gamma-rays from electromagnetic cascades inside massive binaries

Production and the escape of high energy gamma rays from a close massive binary system which contains a young neutron star are analyzed. It is assumed that gamma rays are produced in the Inverse Compton cascade initiated by relativistic leptons injected by the pulsar into the radiation field of a massive star. The effects of propagation of secondary leptons in the magnetic field of the massive star on the escaping gamma-ray spectra are also considered. We calculate the spectra of gamma-rays which escape to observer located in different directions with respect to the plane of the binary system for the parameters supposed to characterize the massive binary Cyg X-3. This model predicts negative correlation of the gamma-ray light curves observed from such massive binaries in the energy ranges below and above similar to 100 GeV, i.e. between the satellite and ground Cherenkov observatories.