GRB 090510: a genuine short GRB from a binary neutron star coalescing into a Kerr-Newman black hole
- Dipartimento di Fisica, Sapienza Università di Roma and ICRA, Piazzale Aldo Moro 5, I-00185 Roma (Italy)
- ICRA and Unit of Nonlinear Physics and Mathematical Modeling, Department of Engineering, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, I-00128, Rome (Italy)
- University of Siena, Department of Physical Sciences, Earth and Environment, Via Roma 56, I-53100 Siena (Italy)
In a new classification of merging binary neutron stars (NSs) we separate short gamma-ray bursts (GRBs) into two subclasses. The ones with E{sub iso}≲10{sup 52} erg coalesce to form a massive NS and are indicated as short gamma-ray flashes (S-GRFs). The hardest, with E{sub iso}≳10{sup 52} erg, coalesce to form a black hole (BH) and are indicated as genuine short GRBs (S-GRBs). Within the fireshell model, S-GRBs exhibit three different components: the proper GRB (P-GRB) emission, observed at the transparency of a self-accelerating baryon-e{sup +}e{sup −} plasma; the prompt emission, originating from the interaction of the accelerated baryons with the circumburst medium; and the high-energy (GeV) emission, observed after the P-GRB and indicating the formation of a BH. GRB 090510 gives the first evidence for the formation of a Kerr BH or, possibly, a Kerr–Newman BH. Its P-GRB spectrum can be fitted by a convolution of thermal spectra whose origin can be traced back to an axially symmetric dyadotorus. A large value of the angular momentum of the newborn BH is consistent with the large energetics of this S-GRB, which reach in the 1–10,000 keV range E{sub iso}=(3.95±0.21)×10{sup 52} erg and in the 0.1–100 GeV range E{sub LAT}=(5.78±0.60)×10{sup 52} erg, the most energetic GeV emission ever observed in S-GRBs. The theoretical redshift z{sub th}=0.75±0.17 that we derive from the fireshell theory is consistent with the spectroscopic measurement z=0.903±0.003, showing the self-consistency of the theoretical approach. All S-GRBs exhibit GeV emission, when inside the Fermi-LAT field of view, unlike S-GRFs, which never evidence it. The GeV emission appears to be the discriminant for the formation of a BH in GRBs, confirmed by their observed overall energetics.
- OSTI ID:
- 22868491
- Journal Information:
- Astrophysical Journal, Vol. 831, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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