Magnetic extraction of black hole rotational energy: Method and results of general relativistic magnetohydrodynamic simulations in Kerr space-time

2003 ◽  
Vol 67 (10) ◽  
Author(s):  
Shinji Koide
Keyword(s):  
Black Hole ◽  
Energy Method ◽  
Rotational Energy ◽  
Space Time ◽  
Kerr Space ◽  
General Relativistic ◽  
Magnetohydrodynamic Simulations ◽  
Magnetic Extraction

scholarly journals Extraction of Black Hole Rotational Energy by a Magnetic Field

2003 ◽  
Vol 214 ◽  
pp. 87-90
Author(s):  
Shinji Koide
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Large Scale ◽  
Kerr Black Hole ◽  
Negative Energy ◽  
Rotational Energy ◽  
Alfven Wave ◽  
Numerical Result ◽  
General Relativistic ◽  
Magnetohydrodynamic Simulations

We have developed a numerical method for general relativistic magnetohydrodynamic simulations in Kerr space-time. The method is applied to the basic astrophysical problem of the Kerr black hole activity in the large-scale strong magnetic field. The numerical result shows that the magnetic field extracts the rotational energy of the black hole with negative energy-at-infinity and the torsional Alfven wave is induced from the ergosphere.

scholarly journals Relative depolarization of the black hole photon ring in GRMHD models of Sgr A* and M87*

2021 ◽  
Vol 503 (3) ◽  
pp. 4563-4575
Author(s):  
A Jiménez-Rosales ◽  
J Dexter ◽  
S M Ressler ◽  
A Tchekhovskoy ◽  
M Bauböck ◽  
...  
Keyword(s):  
Black Hole ◽  
Relativistic Effects ◽  
Image Features ◽  
Black Hole Mass ◽  
Magnetic Turbulence ◽  
Intensity Images ◽  
General Relativistic ◽  
Sharp Image ◽  
Sgr A ◽  
Magnetohydrodynamic Simulations

ABSTRACT Using general relativistic magnetohydrodynamic simulations of accreting black holes, we show that a suitable subtraction of the linear polarization per pixel from total intensity images can enhance the photon ring feature. We find that the photon ring is typically a factor of ≃2 less polarized than the rest of the image. This is due to a combination of plasma and general relativistic effects, as well as magnetic turbulence. When there are no other persistently depolarized image features, adding the subtracted residuals over time results in a sharp image of the photon ring. We show that the method works well for sample, viable GRMHD models of Sgr A* and M87*, where measurements of the photon ring properties would provide new measurements of black hole mass and spin, and potentially allow for tests of the ‘no-hair’ theorem of general relativity.

scholarly journals The effects of resolution on black hole accretion simulations of jets

2020 ◽  
Vol 498 (2) ◽  
pp. 2428-2439
Author(s):  
Christopher J White ◽  
Fiona Chrystal
Keyword(s):  
Black Hole ◽  
Velocity Structure ◽  
Grid Resolution ◽  
Black Hole Accretion ◽  
General Relativistic ◽  
Axisymmetric Structure ◽  
Magnetohydrodynamic Simulations ◽  
Jet Power ◽  
Hole Accretion

ABSTRACT We perform three general-relativistic magnetohydrodynamic simulations of black hole accretion designed to test how sensitive results are to grid resolution in the jet region. The cases differ only in numerics, modelling the same physical scenario of a radiatively inefficient, geometrically thick, magnetically arrested flow on to a rapidly spinning black hole. Properties inferred with the coarsest grid generally agree with those found with higher resolutions, including total jet power and its decomposition into different forms, velocity structure, non-axisymmetric structure, and the appearance of resolved millimetre images. Some measures of variability and magnetization are sensitive to resolution. We conclude that most results obtained by limiting resolution near the jet for computational expediency should still be reliable, at least in so far as they would not be improved with a finer grid.

scholarly journals Disc Tearing and Bardeen-Petterson Alignment in GRMHD Simulations of Highly Tilted Thin Accretion Discs

2020 ◽  
Author(s):  
M Liska ◽  
C Hesp ◽  
A Tchekhovskoy ◽  
A Ingram ◽  
M van der Klis ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Nuclei ◽  
Accretion Discs ◽  
Emission Model ◽  
Sharp Drop ◽  
Frame Dragging ◽  
General Relativistic ◽  
Magnetohydrodynamic Simulations ◽  
Future Work ◽  
X Ray Binaries

Abstract Luminous active galactic nuclei (AGN) and X-Ray binaries (XRBs) often contain geometrically thin, radiatively cooled accretion discs. According to theory, these are – in many cases – initially highly misaligned with the black hole equator. In this work, we present the first general relativistic magnetohydrodynamic simulations of very thin (h/r∼0.015-0.05) accretion discs around rapidly spinning (a∼0.9) black holes and tilted by 45-65 degrees. We show that the inner regions of the discs with h/r≲0.03 align with the black hole equator, though out to smaller radii than predicted by analytic work. The inner aligned and outer misaligned disc regions are separated by a sharp break in tilt angle accompanied by a sharp drop in density. We find that frame-dragging by the spinning black hole overpowers the disc viscosity, which is self-consistently produced by magnetized turbulence, tearing the disc apart and forming a rapidly precessing inner sub-disc surrounded by a slowly precessing outer sub-disc. We find that the system produces a pair of relativistic jets for all initial tilt values. At small distances the black hole launched jets precess rapidly together with the inner sub-disc, whereas at large distances they partially align with the outer sub-disc and precess more slowly. If the tearing radius can be modeled accurately in future work, emission model independent measurements of black hole spin based on precession-driven quasi-periodic oscillations may become possible.

scholarly journals General Relativistic Magnetohydrodynamic Simulations of Collapsars: Rotating Black Hole Cases

2004 ◽  
Vol 615 (1) ◽  
pp. 389-401 ◽  
Author(s):  
Yosuke Mizuno ◽  
Shoichi Yamada ◽  
Shinji Koide ◽  
Kazunari Shibata
Keyword(s):  
Black Hole ◽  
Rotating Black Hole ◽  
General Relativistic ◽  
Magnetohydrodynamic Simulations

scholarly journals Shadow of a Kerr-like black hole

2014 ◽  
Vol 10 (S312) ◽  
pp. 135-136
Author(s):  
Farruh Atamurotov
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Deformation Parameter ◽  
Space Time ◽  
Black Hole Spin ◽  
Spin Parameter ◽  
Kerr Space ◽  
The One

AbstractThe shadow of a Kerr-like black hole has been considered and it was shown that in addition to the specific angular momentum a, deformation parameter of Kerr-like space-time essentially deforms the shape of the black hole shadow. For a given value of the black hole spin parameter a, the presence of a deformation parameter ε reduces the shadow and enlarges its deformation with respect to the one in the Kerr space-time.

The gravitational perturbations of the Kerr black hole IV. The completion of the solutiont

1980 ◽  
Vol 372 (1751) ◽  
pp. 475-484 ◽  
Keyword(s):  
Black Hole ◽  
Kerr Black Hole ◽  
Space Time ◽  
Gravitational Perturbations ◽  
Kerr Space ◽  
The One

This paper eliminates the last remaining lacuna in the information that was needed to make the solution for the perturbations in the metric coefficients of the Kerr space-time fully explicit. The requisite information is obtained from a pair of equations which is complementary to the one considered in paper III; and the solution of the Newman-Penrose equations governing the perturbations is, thus, completed.

scholarly journals Brightness Asymmetry of Black Hole Images as a Probe of Observer Inclination

2022 ◽  
Vol 924 (2) ◽  
pp. 46
Author(s):  
Lia Medeiros ◽  
Chi-Kwan Chan ◽  
Ramesh Narayan ◽  
Feryal Özel ◽  
Dimitrios Psaltis
Keyword(s):  
Black Hole ◽  
Necessary Condition ◽  
Flow Models ◽  
Supermassive Black Hole ◽  
The North ◽  
North Side ◽  
Test Particles ◽  
Angular Velocities ◽  
General Relativistic ◽  
Magnetohydrodynamic Simulations

Abstract The Event Horizon Telescope recently captured images of the supermassive black hole in the center of the M87 galaxy, which shows a ring-like emission structure with the south side only slightly brighter than the north side. This relatively weak asymmetry in the brightness profile along the ring has been interpreted as a consequence of the low inclination of the observer (around 17° for M87), which suppresses the Doppler beaming and boosting effects that might otherwise be expected due to the nearly relativistic velocities of the orbiting plasma. In this work, we use a large suite of general relativistic magnetohydrodynamic simulations to reassess the validity of this argument. By constructing explicit counterexamples, we show that low inclination is a sufficient but not necessary condition for images to have low brightness asymmetry. Accretion flow models with high accumulated magnetic flux close to the black hole horizon (the so-called magnetically arrested disks) and low black hole spins have angular velocities that are substantially smaller than the orbital velocities of test particles at the same location. As a result, such models can produce images with low brightness asymmetry even when viewed edge on.

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