Journal Article

A disc–corona model for a rotating black hole

Xiao-Long Gong, Li-Xin Li and Ren-Yi Ma

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 420, issue 2, pages 1415-1422
Published in print February 2012 | ISSN: 0035-8711
Published online January 2012 | e-ISSN: 1365-2966 | DOI:
A disc–corona model for a rotating black hole

Show Summary Details


We propose a disc–corona model in which a geometrically thin, optically thick disc surrounds a Kerr black hole, and magnetic fields exert a time-steady torque on the inner edge of the accretion disc. The analytical expression of the total gravitational power is derived from the thin-disc dynamics equations by using this new boundary condition. It is shown that the magnetic torque can considerably enhance the amount of energy released in the disc–corona system. Furthermore, the global solutions of this disc–corona system are obtained numerically. We find that the fraction of the power dissipated into the corona in the total for such a disc–corona system increases with increasing dimensionless black hole spin parameter a*, but is insensitive to Δɛ which is the additional radiative efficiency parameter relevant to magnetic torque, for Δɛ > 1. In addition, the emerged spectra from this disc–corona system are simulated by using the Monte Carlo method, and the effect of the different parameters on the output spectra is discussed.

Keywords: accretion, accretion discs; black hole physics; magnetic fields

Journal Article.  4981 words.  Illustrated.

Subjects: Astronomy and Astrophysics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.