scholarly journals The Fe Kα Line and Relativistic Effects from Accretion Disks

1997 ◽  
Vol 163 ◽  
pp. 27-37
Author(s):  
Randy R. Ross
Keyword(s):  
Black Hole ◽  
Accretion Disks ◽  
Relativistic Effects ◽  
Line Profiles ◽  
Black Hole Accretion ◽  
Hole Accretion

AbstractOne of the most exciting results from ASCA has been the discovery of relativistic line profiles for iron Kα emission from Seyfert 1 galaxies. Recent results concerning the properties of Fe Kα lines from the inner regions of black-hole accretion disks are reviewed.

scholarly journals High-Frequency QPOs and Overstable Oscillations of Black-Hole Accretion Disks

2012 ◽  
Vol 8 (S290) ◽  
pp. 57-61 ◽  
Author(s):  
Dong Lai ◽  
Wen Fu ◽  
David Tsang ◽  
Jiri Horak ◽  
Cong Yu
Keyword(s):  
Black Hole ◽  
Accretion Disks ◽  
High Frequency ◽  
Oscillation Mode ◽  
Relativistic Effects ◽  
X Ray ◽  
Black Hole Accretion ◽  
General Relativistic ◽  
X Ray Binaries ◽  
Hole Accretion

AbstractThe physical origin of high-frequency QPOs (HFQPOs) in black-hole X-ray binaries remains an enigma despite many years of detailed observational studies. Although there exists a number of models for HFQPOs, many of these are simply “notions” or “concepts” without actual calculation derived from fluid or disk physics. Future progress requires a combination of numerical simulations and semi-analytic studies to extract physical insights. We review recent works on global oscillation modes in black-hole accretion disks, and explain how, with the help of general relativistic effects, the energy stored in the disk differential rotation can be pumped into global spiral density modes in the disk, making these modes grow to large amplitudes under certain conditions (“corotational instability”). These modes are robust in the presence of disk magnetic fields and turbulence. The computed oscillation mode frequencies are largely consistent with the observed values for HFQPOs in BH X-ray binaries. The approximate 2:3 frequency ratio is also expected from this model. The connection of HFQPOs with other disk properties (such as production of episodic jets) is also discussed.

Iron Fluorescence from within the Innermost Stable Orbit of Black Hole Accretion Disks

1997 ◽  
Vol 488 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Christopher S. Reynolds ◽  
Mitchell C. Begelman
Keyword(s):  
Black Hole ◽  
Accretion Disks ◽  
Stable Orbit ◽  
Black Hole Accretion ◽  
Hole Accretion

scholarly journals Black Hole Accretion Disks on the Edge

2003 ◽  
Vol 596 (1) ◽  
pp. 414-420 ◽  
Author(s):  
Kristen Menou
Keyword(s):  
Black Hole ◽  
Accretion Disks ◽  
Black Hole Accretion ◽  
Hole Accretion

scholarly journals Low-frequency, one-armed oscillations in black hole accretion flows obtained from direct 3D MHD simulations

2006 ◽  
Vol 2 (S238) ◽  
pp. 405-406
Author(s):  
Mami Machida ◽  
Ryoji Matsumoto
Keyword(s):  
Black Hole ◽  
Low Frequency ◽  
Maximum Velocity ◽  
Relativistic Effects ◽  
Newtonian Potential ◽  
Opening Angle ◽  
Accretion Flows ◽  
Black Hole Accretion ◽  
Mhd Simulations ◽  
Hole Accretion

AbstractWe present the results of global 3D MHD simulations of optically thin black hole accretion flows. The initial disk is embedded in a low density, spherical, isothermal halo and threaded by weak (β ≡ Pgas/Pmag = 100) toroidal magnetic field. General relativistic effects are simulated by using the pseudo-Newtonian potential. When the Maxwell stress in the innermost region of the disk is reduced due to the loss of magnetic flux or by decrease of disk temperature, inner torus is created around 4 – 10rs. We found that in such an inner torus, one-armed (m = 1) density enhancement grows and that the inner torus oscillates quasi-periodically. The oscillation period is about 0.1s when we assume a 10M⊙ black hole. This frequency agrees with the low-frequency QPOs observed in low/hard state of black hole candidates. The disk ejects winds whose opening angle is about 30 degree. The maximum velocity of the wind is about 0.05c.

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