The conical morphology, jetted GeV emission, and X-ray afterglows of long GRBs

Context. We review evidence that all short and long GRBs have binary progenitors. Among them, the progenitor of BdHNe consists of a carbon-oxygen core (CO_core) and a binary neutron star (NS) companion. For binary periods as short as 5 min, the special energetic subclass BdHN I originates from the CO_core collapse. In some cases only, further accretion onto the BH leads to GeV emission with an isotropic luminosity L_GeV ∝ t^{−1.19±0.04}. 3) The new NS (νNS)created by the SN accretes SN material giving origin to the X-ray afterglow with L_X ∝ t^{−1.48±0.32}, always present in all BdHN I.
Conclusions. In BdHN I the BH originates from the gravitational collapse of the companion following the SN hypercritical accretion. The GeV rest-frame luminosity follows a universal power-law of index −1.19±0.04, and is jetted with a 60° angle. We estimate the evolution of the mass and the spin of their BH and verify, for the first time, the validity of the BH extractable energy formula. From their X-ray afterglow luminosity, we determine the spin of the νNS consistently below their maximum theoretical value. The presence of the afterglow emission in all observed BdHN families clearly points to a process occurring with very wide-angle emission.