A Measurement of the Electromagnetic Luminosity of a Kerr Black Hole

dc.creatorMcKinney, Jonathan C.
dc.creatorGammie, Charles F.
dc.date2004-04-26
dc.date.accessioned2026-07-07T10:27:12Z
dc.date.available2026-07-07T10:27:12Z
dc.descriptionSome active galactic nuclei, microquasars, and gamma ray bursts may be powered by the electromagnetic braking of a rapidly rotating black hole. We investigate this possibility via axisymmetric numerical simulations of a black hole surrounded by a magnetized plasma. The plasma is described by the equations of general relativistic magnetohydrodynamics, and the effects of radiation are neglected. The evolution is followed for $2000 G M/c^3$, and the computational domain extends from inside the event horizon to typically $40 G M/c^2$. We compare our results to two analytic steady state models, including the force-free magnetosphere of Blandford & Znajek. Along the way we present a self-contained rederivation of the Blandford-Znajek model in Kerr-Schild (horizon penetrating) coordinates. We find that (1) low density polar regions of the numerical models agree well with the Blandford-Znajek model; (2) many of our models have an outward Poynting flux on the horizon in the Kerr-Schild frame; (3) none of our models have a net outward energy flux on the horizon; and (4) one of our models, in which the initial disk has net magnetic flux, shows a net outward angular momentum flux on the horizon. We conclude with a discussion of the limitations of our model, astrophysical implications, and problems to be addressed by future numerical experiments.
dc.description45 pages, 11 Postscript figures, 4 tables, uses subfigure.sty, ApJ, in press
dc.identifierhttps://arxiv.org/abs/astro-ph/0404512
dc.identifierhttp://arxiv.org/abs/astro-ph/0404512
dc.identifierAstrophys.J.611:977-995,2004
dc.identifierdoi:10.1086/422244
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/177084
dc.subjectAstrophysics
dc.titleA Measurement of the Electromagnetic Luminosity of a Kerr Black Hole
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