The Blackholic energy and the canonical Gamma‐Ray Burst IV: the “long,” “genuine short” and “fake—disguised short” GRBs

We report some recent developments in the understanding of GRBs based on the theoretical framework of the “fireshell” model, already presented in the last three editions of the “Brazilian School of Cosmology and Gravitation.” After recalling the basic features of the “fireshell model,” we emphasize the following novel results: 1) the interpretation of the X‐ray flares in GRB afterglows as due to the interaction of the optically thin fireshell with isolated clouds in the CircumBurst Medium (CBM); 2) an interpretation as “fake—disguised” short GRBs of the GRBs belonging to the class identified by Norris & Bonnell; we present two prototypes, GRB 970228 and GRB 060614; both these cases are consistent with an origin from the final coalescence of a binary system in the halo of their host galaxies with particularly low CBM density ncbm∼10−3 particles/cm3; 3) the first attempt to study a genuine short GRB with the analysis of GRB 050509B, that reveals indeed still an open question; 4) the interpretation of the GR...