Gamma-Ray Bursts from Neutron Star Binaries

We report on general relativistic hydrodynamic studies which indicate several new physical processes which may contribute to powering gamma-ray bursts in neutron star binaries. Relativistically driven compression, heating, and collapse of the individual stars can occur many seconds before inspiral and merger. This compression may produce a neutrino burst of $\sim 10^{53}$ ergs lasting several seconds. The associated thermal neutrino emission produces an $e^+-e^-$ pair plasma by $\nu \bar \nu$ annihilation. We show first results of a simulated burst which produces $\sim 10^{51}$ erg in $\gamma$-rays. We also discuss a preliminary study of the evolution of the magnetic field lines attached to the fluid as the stars orbit. We show that the relativistically driven fluid motion might lead to the formation of extremely strong magnetic fields ($\sim 10^{17}$ gauss) in and around the stars which could affect to the formation and evolution of a gamma-ray burst.