A double component in GRB 090618: a proto-black hole and a genuinely long gamma-ray burst

The joint X-ray and gamma-ray observations of GRB 090618 by very many satellites offer an unprecedented possibility of testing crucial aspects of theoretical models. The authors test the fireshell model of GRBs in one of the closest and most energetic GRBs, namely GRB 090618. They analyzed the emission from GRB 090618 using several spectral models, with special attention to the thermal and powerlaw components. They determined the fundamental parameters of a canonical GRB within the context of the fireshell model. They find evidence of the existence of two different episodes in GRB 090618. The first episode lasts 50 s and is characterized by a spectrum consisting of a thermal component, and a power law with an average index ... . The second episode, a temperature at transparency of 29.22 keV and with a characteristic size of the surrounding clouds of ... and masses of ... (ProQuest: ... denotes formulae/symbols omitted.)