On The Origin of Gamma Ray Bursts
  We propose that repeated photoexcitation/ionization of high Z atoms of highly relativistic flows by star light in dense stellar regions followed by emission of decay/recombination photons, which are beamed and boosted to gamma ray energies in the observer frame, produce gamma ray bursts (GRBs). We show that this overlooked mechanism, which is able to convert efficiently baryonic kinetic energy release in merger or accretion induced collapse of neutron stars into cosmological GRBs, reproduces remarkably well all the main observed properties of GRBs. 
Nir J. Shaviv, Arnon Dar (Israel Institute of Technology)