SPECTRAL SIGNATURES OF THE MEV-PEV RADIATION FROM ACCRETING NEUTRON-STARS

We discuss the formation of the high-energy gamma-ray and neutrino spectrum produced by the injection of a power-law proton distribution extending up to E(p) approximately 10(16) eV in the magnetosphere of accreting neutron stars. The resulting proton spectrum is calculated in the presence of advection and cooling by interactions with the X-ray spectrum of the neutron star, leading to several components of a secondary photon spectrum extending from the MeV to the PeV range, and a neutrino spectrum extending from about 0.1 TeV to 0.1 PeV. The shapes of the resulting high-energy secondary spectra depend sensitively on the accreting source's X-ray spectrum and energy density as well as the magnetic field strength involved. Detailed spectra are calculated for the specific examples of Her X-1 and Cyg X-3.