Escape of VHE gamma-rays from close massive binary Centauri X-3

We consider propagation of very high energy (VHE) gamma-rays in the radiati on field of a massive star in the binary system Cen X-3. which has been rep orted as a source of gamma-ray photons in the GeV and TeV energies. VHE gam ma-rays or electrons. injected by the compact object, should develop invers e Compton e(+/-) pair cascades. Based on the Monte Carlo simulations we pre dict the gamma -ray spectra and the gamma -ray light curves for the paramet ers of Cen X-3 system, and applying different models of injection of primar y particles (monodirectional, isotropic, monoenergetic, power law). It is f ound that the gamma-ray spectra observed at different directions have diffe rent shapes and intensities. Interestingly, some gamma-rays may even escape from the binary system at directions which are obscured by the massive sta r, i.e. from the opposite side of the massive star to the location of the c ompact source of primary gamma-rays or electrons. We predict that the gamma ray light curves, produced in the case of electron injection by the compac t object in the Cen X-3 system, should have opposite tendencies for photons with energies above 100 MeV and above 300 GeV, i.e. the photon intensities increase with phase in the first case and decrease with phase in the secon d case. However the model with injection of primary electrons seems to be c ontrary to the reported modulation of the GeV gamma -ray flux with the puls ar's period. The model with injection of primary photons allows such modula tion with the pulsar's period, but predicts strong modulation of the TeV fl ux with the orbital period of the binary. Modulation of TeV emission with t he orbital period was reported by the early Cherenkov observations, but was not confirmed by the recent, more sensitive observations by the Durham Mar k 6 telescope.