Anisotropic scattering from the circumstellar disc in PSR B1259-63

Abstract: The gamma-ray binary system PSR B1259-63 has recently passed through periastron and has been of particular interest as it was observed by Fermi near the December 2010 periastron passage. The system has been detected at very high energies with H.E.S.S. The most probable production mechanism is inverse Compton scattering between target photons from the optical companion and disc, and relativistic electrons in the pulsar wind. We present results of a full anisotropic inverse Compton scattering model of the system, taking into account the IR excess from the extended circumstellar disc around the optical companion.