High-energy cosmic rays from galactic and extragalactic γ-ray bursts

A model for high-energy (greater than or similar to 10(14) eV) cosmic rays (HECRs) from galactic and extragalactic gamma (GRBs) is summarized. Relativistic outflows in GRBs are assumed to inject power-law distributions of CR protons and ions to the highest (greater than or similar to 10(20) eV) energies. A diffusive propagation model for HECRs from a single recent GRB within approximate to 1 kpc from Earth explains the CR spectrum near and above the knee. The CR spectrum at energies above similar to10(18) eV is fit with a component from extragalactic GRBs. By normalizing the energy injection rate to that required to produce the CR flux from extragalactic sources observed locally, we determine the amount of energy a typical GRB must release in the form of nonthermal hadrons. Our interpretation of the HECR spectrum requires that GRBs are hadronically dominated, which would be confirmed by the detection of HE neutrinos from GRBs.