General Relativistic Effects on the Spectrum Reflected by Accretion Disks around Black Holes

1998 ◽  
Vol 504 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Gang Bao ◽  
Paul J. Wiita ◽  
Petr Hadrava
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Relativistic Effects ◽  
General Relativistic

Beyond the Schwarzschild Metric

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Test Particle ◽  
Direct Detection ◽  
Relativistic Effects ◽  
Big Bang ◽  
Clusters Of Galaxies ◽  
General Relativistic ◽  
The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

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.

scholarly journals Alignment of Magnetized Accretion Disks and Relativistic Jets with Spinning Black Holes

Science ◽  
2012 ◽  
Vol 339 (6115) ◽  
pp. 49-52 ◽  
Author(s):  
Jonathan C. McKinney ◽  
Alexander Tchekhovskoy ◽  
Roger D. Blandford
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Three Dimensional ◽  
Host Galaxies ◽  
Relativistic Jets ◽  
Outer Disk ◽  
Alignment Mechanism ◽  
General Relativistic ◽  
Thin Disks ◽  
Intense Radiation

Accreting black holes (BHs) produce intense radiation and powerful relativistic jets, which are affected by the BH’s spin magnitude and direction. Although thin disks might align with the BH spin axis via the Bardeen-Petterson effect, this does not apply to jet systems with thick disks. We used fully three-dimensional general relativistic magnetohydrodynamical simulations to study accreting BHs with various spin vectors and disk thicknesses and with magnetic flux reaching saturation. Our simulations reveal a “magneto-spin alignment” mechanism that causes magnetized disks and jets to align with the BH spin near BHs and to reorient with the outer disk farther away. This mechanism has implications for the evolution of BH mass and spin, BH feedback on host galaxies, and resolved BH images for the accreting BHs in SgrA* and M87.

scholarly journals Accretion disks around binary black holes of unequal mass: General relativistic magnetohydrodynamic simulations near decoupling

2014 ◽  
Vol 89 (6) ◽  
Author(s):  
Roman Gold ◽  
Vasileios Paschalidis ◽  
Zachariah B. Etienne ◽  
Stuart L. Shapiro ◽  
Harald P. Pfeiffer
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Binary Black Holes ◽  
Unequal Mass ◽  
General Relativistic ◽  
Magnetohydrodynamic Simulations

scholarly journals Large-scale dynamo of accretion disks around supermassive nonrotating black holes

2006 ◽  
pp. 49-55
Author(s):  
A.L. Poplavsky ◽  
O.P. Kuznechik ◽  
N.I. Stetyukevich
Keyword(s):  
Magnetic Field ◽  
Black Holes ◽  
Active Galactic Nuclei ◽  
Accretion Disks ◽  
Large Scale ◽  
Temporal Distribution ◽  
Galactic Nuclei ◽  
Dynamo Action ◽  
Stable Circular Orbit ◽  
General Relativistic

In this paper one presents an analytical model of accretion disk magnetosphere dynamics around supermassive nonrotating black holes in the centers of active galactic nuclei. Based on general relativistic equations of magneto hydrodynamics, the nonstationary solutions for time-dependent dynamo action in the accretion disks, spatial and temporal distribution of magnetic field are found. It is shown that there are two distinct stages of dynamo process: the transient and the steady-state regimes, the induction of magnetic field at t > 6:6665 x 1011GM/c3 s becomes stationary, magnetic field is located near the innermost stable circular orbit, and its value rises up to ~ 105 G. Applications of such systems with nonrotating black holes in real active galactic nuclei are discussed.

scholarly journals The Spectrum of Massive Thin Accretion Disks: Theory and Observations

1989 ◽  
Vol 134 ◽  
pp. 251-252
Author(s):  
Ari Laor
Keyword(s):  
Angular Distribution ◽  
Temperature Gradient ◽  
Accretion Disks ◽  
Electron Scattering ◽  
Accretion Rate ◽  
Relativistic Effects ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Scattering Effects ◽  
General Relativistic

We have made detailed calculations of the structure and the spectrum of massive, geometrically thin “bare” accretion disks. The calculations are for an α-disk with various assumptions on the viscosity law. The radiative transfer was treated with the Eddington approximation for an atmosphere with a vertical temperature gradient. All significant sources of opacity, for T>104K, are included, and all models are found to be optically thick throughout. Spectral modifications due to electron scattering (modified blackbody and comptonization) are not significant in most cases. The requirement of a geometrically thin accretion disk forces a limit of L<0.3Led on the accretion rate. Several previous disk calculations violate this limit (Malkan 1983, Czerny & Elvis 1987, Bechtold et al. 1987) and their results are questionable. The surface temperature is close to the effective temperature, even for regions where electron scattering effects are significant. This is due to the vertical temperature gradient and is in contradiction to earlier findings. The angular distribution of the ionizing flux is strongly influenced by general relativistic effects, and can be very different for various disks.

General Relativistic Simulations of Accretion Disks Around Tilted Kerr Black Holes

2014 ◽  
pp. 121-127
Author(s):  
Vassilios Mewes ◽  
Pedro J. Montero ◽  
Nikolaos Stergioulas ◽  
Filippo Galeazzi ◽  
José A. Font
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
General Relativistic ◽  
Kerr Black Holes
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