MeV-GeV Emission from Neutron-loaded Short Gamma-Ray Burst Jets

Recent discovery of the afterglow emission from short gamma-ray bursts suggests that binary neutron star or black hole-neutron star binary mergers are the likely progenitors of these short bursts. The accretion of neutron star material and its subsequent ejection by the central engine implies a neutron-rich outflow. We consider here a neutron-rich relativistic jet model of short bursts and investigate the high-energy neutrino and photon emission as neutrons and protons decouple from each other. We find that upcoming neutrino telescopes are unlikely to detect the 50 GeV neutrinos expected in this model. For bursts at z~0.1, we find that the Gamma-Ray Large Area Space Telescope (GLAST) and ground-based Cerenkov telescopes should be able to detect prompt 100 MeV and 100 GeV photon signatures, respectively, which may help test the neutron star merger progenitor identification.