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 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 Tracking the moving optical photocenters of active galaxies: binary black holes, accretion disks and relativistic jets

2003 ◽  
Author(s):  
Ann E. Wehrle ◽  
Stephen C. Unwin ◽  
Dayton L. Jones ◽  
David L. Meier ◽  
B. G. Piner
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Active Galaxies ◽  
Relativistic Jets ◽  
Binary Black Holes

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 Relativistic Particle Transport in Hot Accretion Disks

1994 ◽  
Vol 142 ◽  
pp. 949-953
Author(s):  
Peter A. Becker ◽  
Menas Kafatos ◽  
Michael Maisack
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Relativistic Particle ◽  
High Energy ◽  
Black Hole Mass ◽  
Radiation Mechanisms ◽  
Accretion Rates ◽  
Inner Region ◽  
Two Temperature ◽  
Intense Radiation

AbstractAccretion disks around rapidly rotating black holes provide one of the few plausible models for the production of intense radiation in AGNs above energies of several hundred MeV. The rapid rotation of the hole increases the binding energy per nucleon in the last stable orbit relative to the Schwarzschild case, and naturally leads to ion temperatures in the range 1012 -1013 K for sub-Eddington accretion rates. The protons in the hot inner region of a steady, two-temperature disk form a reservoir of energy that is sufficient to power the observed EGRET outbursts if the black hole mass is 1010M⊙ . Moreover, the accretion timescale for the inner region is comparable to the observed transient timescale of ~1 week. Hence EGRET outbursts may be driven by instabilities in hot, two-temperature disks around supermassive black holes. In this paper we discuss turbulent (stochastic) acceleration in hot disks as a possible source of GeV particles and radiation. We constrain the model by assuming the turbulence is powered by a collective instability that drains energy from the hot protons. We also provide some ideas concerning new, high-energy Penrose processes that produce GeV emission be directly tapping the rotational energy of Kerr black holes.Subject headings: acceleration of particles — accretion, accretion disks — galaxies: nuclei — quasars: individual (3C 279) — radiation mechanisms: nonthermal

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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