Observational signatures of the magnetic connection between a black hole and a disk

Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA

Corresponding author: lli@cfa.harvard.edu

Received: 14 January 2002
Accepted: 19 June 2002

Abstract

We use a simple model to demonstrate the observational signatures of the magnetic connection between a black hole and a disk: (1) with the existence of the magnetic connection, more energy is dissipated in and radiated away from regions close to the center of the disk; (2) the magnetic connection can produce a very steep emissivity compared to the standard disk accretion; (3) the observational spectral signature of the magnetic connection can be robust. These signatures can be identified by the observations of Chandra and XMM-Newton. In fact, the steep emissivity index for the Seyfert 1 galaxies MCG–6-30-15 and Mrk-766 inferred from the recent XMM-Newton observations is very difficult to be explained with a standard accretion disk but can be easily explained with the magnetic connection between a black hole and a disk.