GRB 080319B: A naked-eye burst powered by unmagnetized internal shocks

GRB 080319B was a very bright gamma‐ray burst with a total isotropic energy ∼1054 erg. It was also distinguished by the strong prompt optical emission with a peak magnitude ∼5th. In this work we interpret the prompt optical (soft γ—ray) emission as the synchrotron (synchrotron self‐Compton) radiation of internal shocks at a rather large radius ∼1016 cm. In this model, the GRB outflow is baryonic rather than Poynting‐flux dominated. The 2nd‐order Inverse Compton radiation of the internal shocks may have not been effectively suppressed and a GeV‐TeV flare as energetic as the keV—MeV emission is plausible, which is detectable by a satellite like GLAST or AGILE.