A Measurement of the Electromagnetic Luminosity of a Kerr Black Hole

McKinney, Jonathan C.; Gammie, Charles F.

doi:10.1086/422244

Cited by 574 publications

(866 citation statements)

References 48 publications

(57 reference statements)

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“…Assuming that the jet power increases with BH spin as P j ∼ a 2 * (McKinney & Gammie 2004;Blandford & Znajek 1977), the discrepancy between halo and core jet power cannot be removed even if an extremely fast-rotating BH (a * = 0.998) is assumed. The most likely explanation is probably that the accretion rate is much lower now than it was a few million years ago.…”

Section: The Jet Powermentioning

confidence: 99%

General relativistic magnetohydrodynamical simulations of the jet in M 87

Mościbrodzka

Falcke

Shiokawa

2016

A&A

294

314

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Context. The connection between black hole, accretion disk, and radio jet can be constrained best by fitting models to observations of nearby low-luminosity galactic nuclei, in particular the well-studied sources Sgr A* and M 87. There has been considerable progress in modeling the central engine of active galactic nuclei by an accreting supermassive black hole coupled to a relativistic plasma jet. However, can a single model be applied to a range of black hole masses and accretion rates? Aims. Here we want to compare the latest three-dimensional numerical model, originally developed for Sgr A* in the center of the Milky Way, to radio observations of the much more powerful and more massive black hole in M 87. Methods. We postprocess three-dimensional GRMHD models of a jet-producing radiatively inefficient accretion flow around a spinning black hole using relativistic radiative transfer and ray-tracing to produce model spectra and images. As a key new ingredient in these models, we allow the proton-electron coupling in these simulations depend on the magnetic properties of the plasma. Results. We find that the radio emission in M 87 is described well by a combination of a two-temperature accretion flow and a hot single-temperature jet. Most of the radio emission in our simulations comes from the jet sheath. The model fits the basic observed characteristics of the M 87 radio core: it is "edge-brightened", starts subluminally, has a flat spectrum, and increases in size with wavelength. The best fit model has a mass-accretion rate ofṀ ∼ 9 × 10 −3 M yr −1 and a total jet power of P j ∼ 10 43 erg s −1 . Emission at λ = 1.3 mm is produced by the counter-jet close to the event horizon. Its characteristic crescent shape surrounding the black hole shadow could be resolved by future millimeter-wave VLBI experiments. Conclusions. The model was successfully derived from one for the supermassive black hole in the center of the Milky Way by appropriately scaling mass and accretion rate. This suggests the possibility that this model could also apply to a wider range of low-luminosity black holes.

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Section: The Jet Powermentioning

confidence: 99%

General relativistic magnetohydrodynamical simulations of the jet in M 87

Mościbrodzka

Falcke

Shiokawa

2016

A&A

294

314

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“…The most successful models are those that involve the extraction of rotational energy from the accretion disk (Blandford & Payne 1982) or of the black hole itself (Blandford & Znajek 1977) through the magnetic field. Some numerical simulations (McKinney & Gammie 2004;De Villiers et al 2005) have suggested that launching from the accretion disk can only produce jets with moderate Lorentz factors (Γ < 3), while a process involving the black hole rotation can achieve Γ ∼ 10 more easily (McKinney 2006). However, it is not ruled out that the inner disk can launch relativistic jets as well (Vlahakis & Königl 2004;Komissarov et al 2007).…”

Section: Introductionmentioning

confidence: 99%

The stratified two-sided jet of Cygnus A

Boccardi

Krichbaum

Bach

et al. 2015

A&A

100

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Aims. High-resolution Very-Long-Baseline Interferometry (VLBI) observations of relativistic jets are essential for constraining the fundamental parameters of jet formation models. At a distance of 249 Mpc, Cygnus A is a unique target for such studies, since it is the only Fanaroff-Riley Class II radio galaxy for which a detailed subparsec scale imaging of the base of both jet and counter-jet can be obtained. Observing at millimeter wavelengths unveils those regions that appear self-absorbed at longer wavelengths and enables an extremely sharp view toward the nucleus to be obtained. Methods. We performed 7 mm Global VLBI observations, achieving ultra-high resolution imaging on scales down to 90 µas. This resolution corresponds to a linear scale of only ∼400 Schwarzschild radii (for M BH = 2.5 × 10 9 M ). We studied the kinematic properties of the main emission features of the two-sided flow and probed its transverse structure through a pixel-based analysis. Results. We suggest that a fast and a slow layer with different acceleration gradients exist in the flow. The extension of the acceleration region is large (∼10 4 R S ), indicating that the jet is magnetically driven. The limb brightening of both jet and counter-jet and their large opening angles (φ J ∼ 10 • ) strongly favour a spine-sheath structure. In the acceleration zone, the flow has a parabolic shape (r ∝ z 0.55 ± 0.07 ). The acceleration gradients and the collimation profile are consistent with the expectations for a jet in "equilibrium", achieved in the presence of a mild gradient of the external pressure (p ∝ z −k , k ≤ 2).

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“…In the past decade, numerical implementations for GRMHD simulation in the fixed gravitational field have been extensively developed (e.g., [18,17,[19][20][21][22][23][24]). In particular, it is worth to mention that Refs.…”

Section: Introductionmentioning

confidence: 99%

Magnetohydrodynamics in full general relativity: Formulation and tests

2005

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A new implementation for magnetohydrodynamics (MHD) simulations in full general relativity (involving dynamical spacetimes) is presented. In our implementation, Einstein's evolution equations are evolved by a BSSN formalism, MHD equations by a high-resolution central scheme, and induction equation by a constraint transport method. We perform numerical simulations for standard test problems in relativistic MHD, including special relativistic magnetized shocks, general relativistic magnetized Bondi flow in stationary spacetime, and a longterm evolution for self-gravitating system composed of a neutron star and a magnetized disk in full general relativity. In the final test, we illustrate that our implementation can follow winding-up of the magnetic field lines of magnetized and differentially rotating accretion disks around a compact object until saturation, after which magnetically driven wind and angular momentum transport inside the disk turn on.04.25. Dm, 04.40.Nr, 47.75.+f, 95.30.Qd

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A Measurement of the Electromagnetic Luminosity of a Kerr Black Hole

Cited by 574 publications

References 48 publications

General relativistic magnetohydrodynamical simulations of the jet in M 87

General relativistic magnetohydrodynamical simulations of the jet in M 87

The stratified two-sided jet of Cygnus A

Magnetohydrodynamics in full general relativity: Formulation and tests

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