A Model for Short Gamma-Ray Bursts: Heated Neutron Stars in Close Binary Systems

Abstract

In this paper we present a model for the short (< second) population of gamma‐ray bursts (GRBs). In this model heated neutron stars in a close binary system near their last stable orbit emit neutrinos at large luminosities (∼ 1053 ergs/sec). A fraction of these neutrinos will annihilate to form an e+e− pair plasma wind which will, in turn, expand and recombine to photons which make the gamma‐ray burst. We study neutrino annihilation and show that a substantial fraction (∼ 1/2) of energy deposited comes from inter‐star neutrinos, where each member of the neutrino pair originates from each neutron star. Thus, in addition to the annihilation of neutrinos blowing off of a single star, we have a new source of baryon free energy that is deposited between the stars. To model the e+e− pair plasma wind between stars, we do three‐dimensional relativistic numerical hydrodynamic calculations. Preliminary results are also presented of new, fully general relativistic calculations of gravitationally attracting stars falling from infinity with no angular momentum. These simulations exhibit a compression effect.