Ackermann, M.M.AckermannAjello, M.M.AjelloAsano, K.K.AsanoCiprini, StefanoStefanoCipriniCutini, SaraSaraCutini2020-09-172020-09-172014-01-01https://hdl.handle.net/20.500.13025/3861Science, Volume 343, Issue 6166, pp. 42-47 (2014).The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest gamma-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.10.1126/science.1242353http://adsabs.harvard.edu/abs/2014Sci...343...42A2014Sci...343...42A