Analysis of the GRB 081024B
Résumé
Recently we proposed the existence of two families of short GRBs, both originating from neutron star mergers: family-1 short bursts with Eiso < 1052 erg and rest-frame spectral peak energy Epeak < 2 MeV, leading to a massive neutron star as the merged core; family-2 short bursts with Eiso > 1052 erg and Epeak > 2 MeV, leading to a black hole as merged core. After the identification of the prototype GRB 090227B and GRB 140619B, we present the results of the analysis of GRB 081024B within the theoretical fireshell model. The presence of a short-lived high energy emission, which is expected to originate from the newly-born black hole, thus places this GRB 081024B among the family-2 short GRBs. From the detailed analysis we derived the redshift of the source z = 2.56 ± 1.63, its isotropic energy Eiso = (1.38 ± 0.78) × 1052 erg, and baryon load B = (5.885 ± 0.42) × 10−5. These values are consistent with the ones found in GRBs 090227B, 090510 and 140619B.