GRBs as ultra-high energy cosmic ray sources: clues from Fermi

Abstract

If gamma-ray bursts are sources of ultra-high energy cosmic rays, then radiative signatures of hadronic acceleration are expected in GRB data. Observations with the Fermi Gamma-ray Space Telescope offer the best means to search for evidence of UHECRs in GRBs through electromagnetic channels. Various issues related to UHECR acceleration in GRBs are reviewed, with a focus on the question of energetics.Comment: 9 pages, to appear in the Proceedings of "The Shocking Universe: Gamma Ray Bursts and High Energy Shock Phenomena," Venice, Italy, 14-18 September 200