Cosmic Rays from Gamma-Ray Bursts in the Galaxy

Abstract

The rate of terrestrial irradiation events by Galactic gamma-ray bursts (GRBs) is estimated using recent standard-energy results. We assume that GRBs accelerate high-energy cosmic rays, and we present results of three-dimensional simulations of cosmic rays moving in the Galactic magnetic field and diffusing through pitch-angle scattering. An on-axis GRB extinction event begins with a powerful prompt gamma-ray and neutron pulse, followed by a longer lived phase from cosmic-ray protons and neutron-decay protons that diffuse toward Earth. Our results force a reinterpretation of reported similar to 10(18) eV cosmic-ray anisotropies and offer a rigorous test of the model in which high-energy cosmic rays originate from GRBs, and this model will soon be tested using the Auger Observatory.