Stability of Accretion Disks around Rotating Black Holes: A Pseudo–General‐Relativistic Fluid Dynamical Study

2003 ◽  
Vol 586 (2) ◽  
pp. 1268-1279 ◽  
Author(s):  
Banibrata Mukhopadhyay
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Dynamical Study ◽  
Relativistic Fluid ◽  
Rotating Black Holes ◽  
General Relativistic

scholarly journals Plasmoid formation in global GRMHD simulations and AGN flares

2020 ◽  
Vol 495 (2) ◽  
pp. 1549-1565 ◽  
Author(s):  
Antonios Nathanail ◽  
Christian M Fromm ◽  
Oliver Porth ◽  
Hector Olivares ◽  
Ziri Younsi ◽  
...  
Keyword(s):  
Black Holes ◽  
Dipolar Field ◽  
Relativistic Jets ◽  
Poloidal Magnetic Field ◽  
Accretion Flows ◽  
Rotating Black Holes ◽  
General Relativistic ◽  
Formation And Evolution ◽  
Magnetohydrodynamic Simulations ◽  
Dissipation Processes

ABSTRACT One of the main dissipation processes acting on all scales in relativistic jets is thought to be governed by magnetic reconnection. Such dissipation processes have been studied in idealized environments, such as reconnection layers, which evolve in merging islands and lead to the production of ‘plasmoids’, ultimately resulting in efficient particle acceleration. In accretion flows on to black holes, reconnection layers can be developed and destroyed rapidly during the turbulent evolution of the flow. We present a series of two-dimensional general-relativistic magnetohydrodynamic simulations of tori accreting on to rotating black holes focusing our attention on the formation and evolution of current sheets. Initially, the tori are endowed with a poloidal magnetic field having a multiloop structure along the radial direction and with an alternating polarity. During reconnection processes, plasmoids and plasmoid chains are developed leading to a flaring activity and hence to a variable electromagnetic luminosity. We describe the methods developed to track automatically the plasmoids that are generated and ejected during the simulation, contrasting the behaviour of multiloop initial data with that encountered in typical simulations of accreting black holes having initial dipolar field composed of one loop only. Finally, we discuss the implications that our results have on the variability to be expected in accreting supermassive black holes.

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 Broad emission lines for a negatively spinning black hole

2010 ◽  
Vol 6 (S275) ◽  
pp. 100-101
Author(s):  
T. Dauser ◽  
J. Wilms ◽  
C. S. Reynolds ◽  
L. W. Brenneman
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Forthcoming Paper ◽  
Emission Lines ◽  
X Ray ◽  
Line Shapes ◽  
Angular Momenta ◽  
Broad Emission ◽  
Rotating Black Holes ◽  
Limb Darkening

AbstractWe present an extended scheme for the calculation of the profiles of emission lines from accretion disks around rotating black holes. The scheme includes disks with angular momenta which are parallel and antiparallel with respect to the black hole's angular momentum, as both configurations are assumed to be stable (King et al. 2005). Based on a Green's function approach, an arbitrary radius dependence of the disk emissivity and arbitrary limb darkening laws can be easily taken into account, while the amount of precomputed data is significantly reduced with respect to other available models. We discuss line shapes for such disks and present a code for modelling observational data with this scheme in X-ray data analysis programs. A detailed discussion will soon be presented in a forthcoming paper (Dauser et al. 2010).

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.

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