Iron Fluorescent Line Emission from Black Hole Accretion Disks with Magnetic Reconnection-heated Corona
Abstract
We investigate the iron Kα fluorescent line produced by hard X-ray photons from the magnetic reconnection-heated corona. The hot corona with temperature of ~109 K can irradiate the underlying disk with a continuum X-ray spectrum produced via thermal Comptonization. Then the iron atoms in the disk photoelectrically absorb X-ray photons and radiate Kα line photons. Therefore, the activity of the corona is responsible for the iron line emission from the underlying disk. In previous studies, oversimplified X-ray photon sources were often assumed above the disk in order to compute the iron line profile or power-law line emissivity profiles were assumed with an index as a free parameter. We adopt the more realistic corona model constructed by Liu et al. in which the corona is heated by magnetic energy released through the reconnection of magnetic flux loops and which has no free parameter. Then the accretion energy is dominantly dissipated in the corona, in which X-ray photons are efficiently produced and irradiate the underlying disk. We find that the local emissivity of the iron line on the disk is approximated as FKα(r)~r-5. The iron line profiles derived from this model give excellent fits to the observational data of MCG -6-30-15 with the profiles derived theoretically for i~30deg for the 4-7 keV energy band. Possible origins of line variability are briefly discussed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- December 2005
- DOI:
- 10.1086/497321
- arXiv:
- arXiv:astro-ph/0508507
- Bibcode:
- 2005ApJ...635..167K
- Keywords:
-
- Accretion;
- Accretion Disks;
- Black Hole Physics;
- Galaxies: Active;
- Line: Profiles;
- Astrophysics
- E-Print:
- 17 pages, 7 figures, accepted for publication in ApJ