There is mounting evidence for the binary nature of the progenitors of gamma-ray bursts (GRBs). For a long GRB, the induced gravitational collapse (IGC) paradigm proposes as progenitor, or "in-state", a tight binary system composed of a carbon-oxygen core (CO core ) undergoing a supernova (SN) explosion which triggers hypercritical accretion onto a neutron star (NS) companion. For a short GRB, a NS-NS merger is traditionally adopted as the progenitor. We divide long and short GRBs into two sub-classes, depending on whether or not a black hole (BH) is formed in the merger or in the hypercritical accretion process exceeding the NS critical mass. For long bursts, when no BH is formed we have the sub-class of X-ray flashes (XRFs), with isotropic energy E iso 10 52 erg and rest-frame spectral peak energy E p,i 200 keV. When a BH is formed we have the sub-class of binary-driven hypernovae (BdHNe), with E iso 10 52 erg and E p,i 200 keV. In analogy, short bursts are similarly divided into two sub-classes. When no BH is formed, short gamma-ray flashes (S-GRFs) occur, with E iso 10 52 erg and E p,i 2 MeV. When a BH is formed, the authentic short GRBs (S-GRBs) occur, with E iso 10 52 erg and E p,i 2 MeV. We give examples and observational signatures of these four sub-classes and their rate of occurrence. From their respective rates it is possible that "in-states" of S-GRFs and S-GRBs originate from the "out-states" of XRFs. We indicate two additional progenitor systems: white dwarf-NS and BH-NS. These systems have hybrid features between long and short bursts. In the case of S-GRBs and BdHNe evidence is given of the coincidence of the onset of the high energy GeV emission with the birth of a Kerr BH.

We have performed our data analysis of the observations by Swift, NuStar and Fermi satellites in order to probe the induced gravitational collapse (IGC) paradigm for GRBs associated with supernovae (SNe), in the "terra incognita" of GRB 130427A. We compare and contrast our data analysis with those in the literature. We have verified that the GRB 130427A conforms to the IGC paradigm by examining the power law behavior of the luminosity in the early 10 4 s of the XRT observations. This has led to the identification of the four different episodes of the "binary driven hypernovae" (BdHNe) and to the prediction, on May 2, 2013, of the occurrence of SN 2013cq, duly observed in the optical band on May 13, 2013. The exceptional quality of the data has allowed the identification of novel features in Episode 3 including: a) the confirmation and the extension of the existence of the recently discovered "nested structure" in the late X-ray luminosity in GRB 130427A, as well as the identification of a spiky structure at 10 2 s in the cosmological rest-frame of the source; b) a power law emission of the GeV luminosity light curve and its onset at the end of Episode 2; c) different Lorentz Γ factors for the emitting regions of the X-ray and GeV emissions in this Episode 3. These results make it possible to test the details of the physical and astrophysical regimes at work in the BdHNe: 1) a newly born neutron star and the supernova ejecta, originating in Episode 1, 2) a newly formed black hole originating in Episode 2, and 3) the possible interaction among these components, observable in the standard features of Episode 3.

We analyze the early X-ray flares in the GRB "flare-plateau-afterglow" (FPA) phase observed by Swift-XRT. The FPA occurs only in one of the seven GRB subclasses: the binary-driven hypernovae (BdHNe). This subclass consists of long GRBs with a carbon-oxygen core and a neutron star (NS) binary companion as progenitors. The hypercritical accretion of the supernova (SN) ejecta onto the NS can lead to the gravitational collapse of the NS into a black hole. Consequently, one can observe a GRB emission with isotropic energy E iso 10 52 erg, as well as the associated GeV emission and the FPA phase. Previous work had shown that gamma-ray spikes in the prompt emission occur at ∼ 10 15 -10 17 cm with Lorentz gamma factor Γ ∼ 10 2 -10 3 . Using a novel data analysis we show that the time of occurrence, duration, luminosity and total energy of the X-ray flares correlate with E iso . A crucial feature is the observation of thermal emission in the X-ray flares that we show occurs at radii ∼ 10 12 cm with Γ 4. These model independent observations cannot be explained by the "fireball" model, which postulates synchrotron and inverse Compton radiation from a single ultra relativistic jetted emission extending from the prompt to the late afterglow and GeV emission phases. We show that in BdHNe a collision between the GRB and the SN ejecta occurs at 10 10 cm reaching transparency at ∼ 10 12 cm with Γ 4. The agreement between the thermal emission observations and these theoretically derived values validates our model and opens the possibility of testing each BdHN episode with the corresponding Lorentz gamma factor.