scholarly journals Why Have the Observed High-frequency QPOs Not Been Produced by (MHD) Computer Simulations of Black Hole Accretion Disks?

2021 ◽  
Vol 5 (11) ◽  
pp. 274
Author(s):  
Robert V. Wagoner ◽  
Celia R. Tandon
Keyword(s):  
Black Hole ◽  
Computer Simulations ◽  
Accretion Disks ◽  
High Frequency ◽  
Black Hole Accretion ◽  
Mhd Simulations ◽  
Numerical Damping ◽  
Hole Accretion

Abstract We compare some predictions of Wagoner & Tandon (WT) with the results of the hydrodynamic and magnetohydrodynamic (MHD) simulations of Reynolds & Miller (RM). It appears that the MHD simulations were not run for long enough and the numerical damping was not small enough to produce the observed high-frequency QPOs (and the g-mode seen in the hydro simulations).

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.

General relativistic MHD simulations of black hole accretion disks and jets

2007 ◽  
Vol 311 (1-3) ◽  
pp. 117-125 ◽  
Author(s):  
John F. Hawley ◽  
Kris Beckwith ◽  
Julian H. Krolik
Keyword(s):  
Black Hole ◽  
Accretion Disks ◽  
Black Hole Accretion ◽  
Mhd Simulations ◽  
General Relativistic ◽  
Hole Accretion

scholarly journals A HIGH-FREQUENCY DOPPLER FEATURE IN THE POWER SPECTRA OF SIMULATED GRMHD BLACK HOLE ACCRETION DISKS

2014 ◽  
Vol 785 (2) ◽  
pp. 142 ◽  
Author(s):  
Sarah Wellons ◽  
Yucong Zhu ◽  
Dimitrios Psaltis ◽  
Ramesh Narayan ◽  
Jeffrey E. McClintock
Keyword(s):  
Black Hole ◽  
Accretion Disks ◽  
High Frequency ◽  
Power Spectra ◽  
Black Hole Accretion ◽  
Hole Accretion

scholarly journals Global 3D MHD Simulations of Optically Thin Black Hole Accretion Disks

2004 ◽  
Vol 155 ◽  
pp. 124-131
Author(s):  
Ryoji Matsumoto ◽  
Mami Machida ◽  
Kenji Nakamura
Keyword(s):  
Black Hole ◽  
Accretion Disks ◽  
Black Hole Accretion ◽  
Mhd Simulations ◽  
Hole Accretion

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
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