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 ∼ 10¹⁶ 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.