SINGLE- AND TWO-COMPONENT GAMMA-RAY BURST SPECTRA IN THEFERMIGBM-LAT ENERGY RANGE

P. Veres, P. Mészáros
2012 Astrophysical Journal  
Most Fermi GRB spectra appear as either a broken power law extending to GeV energies or as a broken power with a separate GeV power law component. Here we show that such spectra can be understood in terms of magnetically dominated relativistic jets where a dissipative photosphere produces the prompt MeV emission, which is extended into the GeV range by inverse Compton scattering in the external shock, with possible contributions from a reverse shock as well. The bulk Lorentz factors required in
more » ... factors required in these models are in the range of 300-600, and the MeV-GeV time delays arise naturally. In some cases an optical flash and a sub-dominant thermal component are also present.
doi:10.1088/0004-637x/755/1/12 fatcat:mg6ckakelzg5bpn5gjbwjrymlq