Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-01-21
Astrophys.J. 624 (2005) 94-102
Astronomy and Astrophysics
Astrophysics
12 pages, 24 figures, ApJ accepted
Scientific paper
10.1086/428875
The assumption that black hole accretion disks possess an untorqued inner boundary, the so-called zero torque boundary condition, has been employed by models of black hole disks for many years. However, recent theoretical and observational work suggests that magnetic forces may appreciably torque the inner disk. This raises the question of the effect that a time-changing magnetic torque may have on the evolution of such a disk. In particular, we explore the suggestion that the ``Deep Minimum State'' of the Seyfert galaxy MCG--6-30-15 can be identified as a sporadic inner disk torquing event. This suggestion is motivated by detailed analyses of changes in the profile of the broad fluorescence iron line in XMM-Newton spectra. We find that the response of such a disk to a torquing event has two phases; an initial damming of the accretion flow together with a partial draining of the disk interior to the torque location, followed by a replenishment of the inner disk as the system achieves a new (torqued) steady-state. If the Deep Minimum State of MCG--6-30-15 is indeed due to a sporadic torquing event, we show that the fraction of the dissipated energy going into X-rays must be smaller in the torqued state. We propose one such scenario in which Compton cooling of the disk corona by ``returning radiation'' accompanying a central-torquing event suppresses the 0.5-10 keV X-ray flux coming from all but the innermost regions of the disk.
Garofalo David
Reynolds Christopher S.
No associations
LandOfFree
Sporadically Torqued Accretion Disks Around Black Holes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Sporadically Torqued Accretion Disks Around Black Holes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sporadically Torqued Accretion Disks Around Black Holes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-592919