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Astron. Astrophys. 350, 334-343 (1999)

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On the pair electromagnetic pulse of a black hole with electromagnetic structure

R. Ruffini 1, J.D. Salmonson 2, J.R. Wilson 2 and S.-S. Xue 1

1 I.C.R.A.-International Center for Relativistic Astrophysics and Physics Department, University of Rome "La Sapienza", I-00185 Rome, Italy
2 Lawrence Livemore National Laboratory, University of California, Livermore, CA, USA

Received 17 March 1999 / Accepted 12 July 1999


We study the relativistically expanding electron-positron pair plasma formed by the process of vacuum polarization around an electromagnetic black hole (EMBH). Such processes can occur for EMBH's with mass all the way up to [FORMULA]. Beginning with a idealized model of a Reissner-Nordstrom EMBH with charge to mass ratio [FORMULA], numerical hydrodynamic calculations are made to model the expansion of the pair-electromagnetic pulse (PEM pulse) to the point that the system is transparent to photons. Three idealized special relativistic models have been compared and contrasted with the results of the numerically integrated general relativistic hydrodynamic equations. One of the three models has been validated: a PEM pulse of constant thickness in the laboratory frame is shown to be in excellent agreement with results of the general relativistic hydrodynamic code. It is remarkable that this precise model, starting from the fundamental parameters of the EMBH, leads uniquely to the explicit evaluation of the parameters of the PEM pulse, including the energy spectrum and the astrophysically unprecedented large Lorentz factors (up to [FORMULA] for a [FORMULA] EMBH). The observed photon energy at the peak of the photon spectrum at the moment of photon decoupling is shown to range from 0.1 MeV to 4 MeV as a function of the EMBH mass. Correspondingly the total energy in photons is in the range of [FORMULA] to [FORMULA] ergs, consistent with observed gamma-ray bursts. In these computations we neglect the presence of baryonic matter which will be the subject of forthcoming publications.

Key words: black hole physics – gamma rays: theory – gamma rays: bursts – gamma rays: observations

© European Southern Observatory (ESO) 1999

Online publication: September 24, 1999