From neutron star binaries to gamma-ray bursts

Rosswog, S. (2005) From neutron star binaries to gamma-ray bursts. Il nuovo cimento C, 28 (4\5). pp. 607-612. ISSN 1826-9885

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Abstract

I summarize recent results about how a neutron star binary coalescence can produce short gamma-ray bursts (GRBs). Two possibilities are discussed: the νi¯νi-annihilation above the merged remnant and the exponential amplification of magnetic fields in the central object up to values close to equipartition. We find that theannihilation of νi¯νi-pairs drives bipolar, relativistic outflows with Lorentzfactors largee nough to circumvent theGRB “compactness problem”. Thetotal energy within these outflows is moderate by GRB-standards (∼ 1048–1049 ergs), but the interaction with the baryonic material blown-off by the neutrinos collimates the outflows into opening angles of typically 0.1 sterad, yielding isotropic energies close to 1051 ergs. We further want to stress the plausibility of the central object resisting the immediate collapse to a black hole. In this case the central object will —similar to a proto-neutron star— be subject to neutrino driven convection that —together with the rapid, differential rotation— will lead to a drastic amplification of preexisting magnetic fields. Within fractions of a second, field strengths comparable to equipartition field strength (> 1017 G) will be reached. These will produce large torques that will spin-down the object within about 0.2 s, and would thus naturally explain the duration of short GRBs.

Item Type: Article
Additional Information: Paper presented at the “4th Workshop on Gamma-Ray Burst in the Afterglow Era”, Rome, October 18-22, 2004.
Uncontrolled Keywords: γ-ray sources, γ-ray bursts
Subjects: 500 Scienze naturali e Matematica > 530 Fisica
Depositing User: Marina Spanti
Date Deposited: 16 Mar 2020 17:38
Last Modified: 16 Mar 2020 17:38
URI: http://eprints.bice.rm.cnr.it/id/eprint/15791

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