TeV gamma-rays from accreting magnetars in massive binaries

This paper focuses on neutron stars (NS) of the magnetar type inside massive binary systems. We determine the conditions under which the matter from the stellar wind can penetrate the inner magnetosphere of the magnetar. At a certain distance from the NS surface, the magnetic pressure can balance the gravitational pressure of the accreting matter, creating a very turbulent, magnetized transition region. It is suggested that this region provides good conditions for the acceleration of electrons to relativistic energies. These electrons lose energy due to the synchrotron process and inverse Compton (IC) scattering of the radiation from the nearby massive stellar companion, producing high-energy radiation from X-rays up to similar to TeV gamma-rays. The primary gamma-rays can be further absorbed in the stellar radiation field, developing an IC e(+/-) pair cascade. We calculate the synchrotron X-ray emission from primary electrons and secondary e(+/-) pairs and the IC gamma-ray emission from the cascade process. It is shown that quasi-simultaneous observations of the TeV gamma-ray binary system LSI +61 303 in the X-ray and TeV gamma-ray energy ranges can be explained with such an accreting magnetar model.