γ-ray production via IC scattering of the infrared excess from the Be-type star in the binary system PSRB1259-63/SS2883

Un-pulsed γ-ray emission has been detected close to periastron in the pulsar/Be-star binary system PSR B1259-63/SS 2883, believed to originate from the shock front that forms between the stellar and pulsar winds. A likely source of γ-ray production is the inverse Compton up-scattering of target photons from the Be star by relativistic electrons/positrons in the pulsar wind. In this study the influence of the infrared radiation, emanating from the circumstellar disc, on isotropic inverse Compton γ-ray production is investigated. It is shown that the scattering of infrared disc photons can increase the γ-ray flux by a factor ∼ 2 in the 1–10 GeV range.