GRB 140619B: A short GRB from a binary neutron star merger leading to black hole formation
Résumé
For short gamma-ray bursts (GRBs), double neutron star (NS) mergers are traditionally adopted as progenitors. We propose a classification of short bursts into two sub-classes: short gamma-ray flashes (S-GRFs) with isotropic energy Eiso ≲ 1052 erg and rest-frame spectral peak energy Ep,i ≲ 2 MeV, when the merger leads to a very massive NS (MNS), and the authentic short GRBs (S-GRBs) with Eiso ≳ 1052 erg and Ep,i ≳ 2 MeV, when a black hole (BH) is formed. Evidences for the BH formation in S-GRBs are provided by the observed high energy 0.1–100 GeV emission after the GRB emission from the e+e−-plasma transparency (P-GRB); in S-GRFs, leading to MNS, this emission is never observed. Both these sub-classes fulfill the Ep,i–Eiso relation for short GRBs. We present here the recently identified S-GRB 140619B. From the spectral analysis of the early ∼ 0.2 s, we infer an observed P-GRB temperature kT = (324 ± 33) keV, a theoretically derived redshift z = 2.67 ± 0.37, a total burst energy 
erg, and a baryon load B = (5.52 ± 0.73) × 10−5. We also estimate the emission of gravitational waves (GWs) of the progenitor NS–NS merger. Including all the S-GRBs so far identified, the observed rate of these sources is 
erg, and a baryon load B = (5.52 ± 0.73) × 10−5. We also estimate the emission of gravitational waves (GWs) of the progenitor NS–NS merger. Including all the S-GRBs so far identified, the observed rate of these sources is