scholarly journals Magnetized accretion disks around Kerr black holes with scalar hair: Constant angular momentum disks

2019 ◽  
Vol 99 (4) ◽  
Author(s):  
Sergio Gimeno-Soler ◽  
José A. Font ◽  
Carlos Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
Accretion Disks ◽  
Scalar Hair ◽  
Kerr Black Holes

scholarly journals Magnetized accretion disks around Kerr black holes with scalar hair: Nonconstant angular momentum disks

2021 ◽  
Vol 104 (10) ◽  
Author(s):  
Sergio Gimeno-Soler ◽  
José A. Font ◽  
Carlos Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
Accretion Disks ◽  
Scalar Hair ◽  
Kerr Black Holes

scholarly journals Circular Orbit Structure and Thin Accretion Disks around Kerr Black Holes with Scalar Hair

2021 ◽  
Vol 910 (1) ◽  
pp. 52
Author(s):  
Lucas G. Collodel ◽  
Daniela D. Doneva ◽  
Stoytcho S. Yazadjiev
Keyword(s):  
Black Holes ◽  
Accretion Disks ◽  
Circular Orbit ◽  
Orbit Structure ◽  
Scalar Hair ◽  
Kerr Black Holes

scholarly journals Growth of accretion driven scalar hair around Kerr black holes

2021 ◽  
Vol 103 (4) ◽  
Author(s):  
Jamie Bamber ◽  
Katy Clough ◽  
Pedro G. Ferreira ◽  
Lam Hui ◽  
Macarena Lagos
Keyword(s):  
Black Holes ◽  
Scalar Hair ◽  
Kerr Black Holes

scholarly journals Gaseous Disks in the Nuclei of Elliptical Galaxies

1997 ◽  
Vol 163 ◽  
pp. 620-625 ◽  
Author(s):  
H. Ford ◽  
Z. Tsvetanov ◽  
L. Ferrarese ◽  
G. Kriss ◽  
W. Jaffe ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Accretion Disks ◽  
Large Scale ◽  
Elliptical Galaxies ◽  
Central Mass ◽  
Massive Black Holes ◽  
Radio Jets

AbstractHST images have led to the discovery that small (r ~ 1″ r ~ 100 – 200 pc), well-defined, gaseous disks are common in the nuclei of elliptical galaxies. Measurements of rotational velocities in the disks provide a means to measure the central mass and search for massive black holes in the parent galaxies. The minor axes of these disks are closely aligned with the directions of the large–scale radio jets, suggesting that it is angular momentum of the disk rather than that of the black hole that determines the direction of the radio jets. Because the disks are directly observable, we can study the disks themselves, and investigate important questions which cannot be directly addressed with observations of the smaller and unresolved central accretion disks. In this paper we summarize what has been learned to date in this rapidly unfolding new field.

scholarly journals Kerr black holes with synchronised scalar hair and higher azimuthal harmonic index

2019 ◽  
Vol 792 ◽  
pp. 436-444 ◽  
Author(s):  
Jorge F.M. Delgado ◽  
Carlos A.R. Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Harmonic Index ◽  
Scalar Hair ◽  
Kerr Black Holes

scholarly journals Launching proton-dominated jets from accreting Kerr Black Holes: the case of M87

2011 ◽  
Vol 1 (1) ◽  
pp. 4 ◽  
Author(s):  
Felix F. Brezinski ◽  
Ahmad A. Hujeirat
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Black Holes ◽  
Angular Momentum ◽  
Event Horizon ◽  
Accretion Disk ◽  
Lorentz Factor ◽  
Spin Parameter ◽  
Low Mass ◽  
Kerr Black Holes

A general relativistic model for the formation and acceleration of low mass-loaded jets from systems containing accreting black holes is presented. The model is based on previous numerical results and theoretical studies in the Newtonian regime, but modified to include the effects of space-time curvature in the vicinity of the event horizon of a spinning black hole. It is argued that the boundary layer between the Keplerian accretion disk and the event horizon is best suited for the formation and acceleration of the accretion-powered jets in active galactic nuclei and micro-quasars. The model presented here is based on matching the solutions of three different regions: i- a weakly magnetized Keplerian accretion disk in the outer part, where the transport of angular momentum is mediated through the magentorotational instability, ii- a strongly magnetized, advection-dominated and turbulent-free boundary layer (BL) between the outer cold accretion disk and the event horizon and where the plasma rotates sub-Keplerian and iii- a transition zone (TZ) between the BL and the overlying corona, where the electrons and protons are thermally uncoupled, highly dissipative and rotate super-Keplerian. In the BL, the gravitation-driven dynamical collapse of the plasma increases the strength of the poloidal magnetic field (PMF) significantly, subsequently suppressing the generation and dissipation of turbulence and turning off the primary source of heating. In this case, the BL appears much fainter than standard disk models so as if the disk truncates at a certain radius. The action of the PMF in the BL is to initiate torsional Alf`ven waves that transport angular momentum from the embedded plasma vertically into the TZ, where a significant fraction of the shear-generated toroidal magnetic field reconnects, thereby heating the protons up to the virial-temperature. Also, the strong PMF forces the electrons to cool rapidly, giving rise therefore to the formation of a gravitationally unbound two-temperature proton-dominated outflow. Our model predicts the known correlation between the Lorentz-factor and the spin parameter of the BH. It also shows that the effective surface of the BL, through which the baryons flow into the TZ, shrinks with increasing the spin parameter, implying therefore that low mass-loaded jets most likely originate from around Kerr black holes. When applying our model to the jet in the elliptical galaxy M87, we find a spin parameter <em>a ∈</em> [0.99, 0.998], a transition radius rtr ≈ 30 gravitational radii and a fraction of 0.05 − 0.1 of the mass accretion rate goes into the TZ, where the plasma speeds up its outward-oriented motion to reach a Lorentz factor Γ <em>∈</em> [2.5, 5.0] at rtr.

scholarly journals How fast can a black hole rotate?

2015 ◽  
Vol 24 (12) ◽  
pp. 1544022 ◽  
Author(s):  
Carlos A. R. Herdeiro ◽  
Eugen Radu
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Mass Formula ◽  
Linear Velocity ◽  
Asymptotically Flat ◽  
Velocity Of Light ◽  
Universal Bound ◽  
Kerr Black Holes

Kerr black holes (BHs) have their angular momentum, [Formula: see text], bounded by their mass, [Formula: see text]: [Formula: see text]. There are, however, known BH solutions violating this Kerr bound. We propose a very simple universal bound on the rotation, rather than on the angular momentum, of four-dimensional, stationary and axisymmetric, asymptotically flat BHs, given in terms of an appropriately defined horizon linear velocity, [Formula: see text]. The [Formula: see text] bound is simply that [Formula: see text] cannot exceed the velocity of light. We verify the [Formula: see text] bound for known BH solutions, including some that violate the Kerr bound, and conjecture that only extremal Kerr BHs saturate the [Formula: see text] bound.

scholarly journals Kerr black holes with parity-odd scalar hair

2019 ◽  
Vol 100 (6) ◽  
Author(s):  
J. Kunz ◽  
I. Perapechka ◽  
Ya. Shnir
Keyword(s):  
Black Holes ◽  
Scalar Hair ◽  
Kerr Black Holes
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