A general relativistic model of accretion disks with coronae surrounding Kerr black holes

Understand

We calculate the structure of a standard accretion disk with corona surrounding a massive Kerr black hole in general relativistic frame, in which the corona is assumed to be heated by the reconnection of the strongly buoyant magnetic fields generated in the cold accretion disk.

• The emergent spectra of the accretion disk-corona systems are calculated by using the relativistic ray-tracing method.
• We propose a new method to calculate the emergent Comptonized spectra from the coronae.
• The spectra of the disk-corona systems with a modified $\alpha$-magnetic stress show that both the hard X-ray spectral index and the hard X-ray bolometric correction factor $L_{\rm bol}/L_{\rm X,2-10keV}$ increase with the dimensionless mass accretion rate, which are qualitatively consistent with the observations of active galactic nuclei (AGNs).