A Measurement of the Electromagnetic Luminosity of a Kerr Black Hole

By J. McKinney, Charles F. Gammie. 2004

505 citations recorded by the source corpus.

Some 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 2000GM/c3, and the computational domain extends from inside the event horizon to typically 40GM/c2. 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.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/bac1dbe039742f7f0e48eb687413aaa78e95e6fc

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In Astronomy and Astrophysics

  1. Ramesh Narayan
  2. J. McKinney
  3. A. Tchekhovskoy
  4. F. Yuan
  5. A. Sa̧dowski
  6. J. E. McClintock
  7. Bing Zhang
  8. A. C. Fabian

In Nuclear and High Energy Physics

  1. Ramesh Narayan
  2. A. Tchekhovskoy
  3. J. McKinney
  4. F. Yuan
  5. A. Sa̧dowski
  6. Bing Zhang
  7. J. E. McClintock
  8. Julian Krolik

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