scholarly journals The energy source of the most energetic giant outbursts in MS 0735 + 7421

2012 ◽  
Vol 8 (S290) ◽  
pp. 257-258
Author(s):  
Shuang-Liang Li
Keyword(s):  
Black Hole ◽  
Blow Up ◽  
Power Source ◽  
Thin Disk ◽  
Jet Formation ◽  
Disk Model ◽  
Black Hole Spin ◽  
Model C ◽  
Jet Power ◽  
Very High

AbstractIn this work, we investigate the power source of the most energetic giant outbursts in MS 0735 + 7421, which released ~ 1062 erg of energy. Due to the very high mean jet power in the cavities (Pjet/LEdd ~ 0.02), we produce several jet formation models based on a relativistic thin disk model, i.e., general BP + BZ mechanisms (model A), Livio's (model B) and Meier's (model C) model, to explain the giant outbursts in AGNs. It is found that the energy provided by both model B and model C are inadequate for an initial black hole spin a0 ~ 0.1, only model A can explain the most violent outbursts in MS 0735 + 7421. But if the initial black hole spin a0 ~ 0.95, model B can also blow up the cavity. The final spin of the black hole is found to be very high in spite of the initial spin.

scholarly journals A thin disk model for the high efficiency jet in powerful lobe-dominated FRII radio galaxies

2016 ◽  
Vol 12 (S324) ◽  
pp. 196-198
Author(s):  
Shuang-Liang Li
Keyword(s):  
Accretion Disk ◽  
High Efficiency ◽  
Radio Galaxies ◽  
Thin Disk ◽  
Disk Model ◽  
Jet Power ◽  
Very High

AbstractWe propose a thin accretion disk with magnetically driven winds model to investigate the high jet efficiency phenomenon in lobe-dominated luminous FRII radio galaxies, which was reported by Fernandes et al. (2011) and Punsly (2011). It was found that the temperature of a thin disk with winds was much lower comparing with that of a standard thin disk because the winds take the most of energy released in the disk away, resulting in a much smaller raditive efficiency. Therefore, the jet efficiency can be very high even for conventional jet power. Our model can explain the observations quite well.

Why only a small fraction of quasars are radio loud?

2018 ◽  
Vol 14 (S342) ◽  
pp. 201-204
Author(s):  
Xinwu Cao
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Angular Momentum ◽  
Angular Velocity ◽  
Strong Magnetic Field ◽  
Weak Magnetic Field ◽  
Thin Disk ◽  
Relativistic Jets ◽  
Jet Formation ◽  
The Magnetic Field

AbstractIt is still a mystery why only a small fraction of quasars contain relativistic jets. A strong magnetic field is a necessary ingredient for jet formation. Gas falls from the Bondi radius RB nearly freely to the circularization radius Rc, and a thin accretion disk is formed within Rc We suggest that the external weak magnetic field threading interstellar medium is substantially enhanced in this region, and the magnetic field at Rc can be sufficiently strong to drive outflows from the disk if the angular velocity of the gas is low at RB. In this case, the magnetic field is efficiently dragged in the disk, because most angular momentum of the disk is removed by the outflows that lead to a significantly high radial velocity. The strong magnetic field formed in this way may accelerate jets in the region near the black hole, either by the Blandford-Payne or/and Blandford-Znajek mechanisms. If the angular velocity of the circumnuclear gas is low, the field advection in the thin disk is inefficient, and it will appear as a radio-quiet (RQ) quasar.

scholarly journals The Brightest Point in Accretion Disk and Black Hole Spin: Implication to the Image of Black Hole M87*

Universe ◽  
2019 ◽  
Vol 5 (8) ◽  
pp. 183 ◽  
Author(s):  
Vyacheslav I. Dokuchaev ◽  
Natalia O. Nazarova
Keyword(s):  
Black Hole ◽  
Event Horizon ◽  
Accretion Disk ◽  
Disk Model ◽  
Dark Region ◽  
High Resolution Image ◽  
Supermassive Black Hole ◽  
Black Hole Spin ◽  
The Galaxy ◽  
Expected Position

We propose the simple new method for extracting the value of the black hole spin from the direct high-resolution image of black hole by using a thin accretion disk model. In this model, the observed dark region on the first image of the supermassive black hole in the galaxy M87, obtained by the Event Horizon Telescope, is a silhouette of the black hole event horizon. The outline of this silhouette is the equator of the event horizon sphere. The dark silhouette of the black hole event horizon is placed within the expected position of the black hole shadow, which is not revealed on the first image. We calculated numerically the relation between the observed position of the black hole silhouette and the brightest point in the thin accretion disk, depending on the black hole spin. From this relation, we derive the spin of the supermassive black hole M87*, a = 0.75 ± 0.15 .

scholarly journals Testing the Kerr Black Hole Hypothesis Using X-Ray Reflection Spectroscopy and a Thin Disk Model with Finite Thickness

2020 ◽  
Vol 899 (1) ◽  
pp. 80 ◽  
Author(s):  
Askar B. Abdikamalov ◽  
Dimitry Ayzenberg ◽  
Cosimo Bambi ◽  
Thomas Dauser ◽  
Javier A. García ◽  
...  
Keyword(s):  
Black Hole ◽  
Finite Thickness ◽  
Kerr Black Hole ◽  
Thin Disk ◽  
Reflection Spectroscopy ◽  
Disk Model ◽  
X Ray

scholarly journals A systematic look at the very high and lowhard state of GX3394: constraining the black hole spin with a new reflection model

2008 ◽  
Vol 387 (4) ◽  
pp. 1489-1498 ◽  
Author(s):  
R. C. Reis ◽  
A. C. Fabian ◽  
R. R. Ross ◽  
G. Miniutti ◽  
J. M. Miller ◽  
...  
Keyword(s):  
Black Hole ◽  
Black Hole Spin ◽  
Reflection Model ◽  
Very High

scholarly journals Magnetohydrodynamics Simulations of Active Galactic Nucleus Disks and Jets

2020 ◽  
Vol 58 (1) ◽  
pp. 407-439
Author(s):  
Shane W. Davis ◽  
Alexander Tchekhovskoy
Keyword(s):  
Black Hole ◽  
Accretion Disk ◽  
Surrounding Medium ◽  
Observational Constraints ◽  
Disk Model ◽  
Accretion Flow ◽  
Accretion Flows ◽  
Black Hole Spin ◽  
Spiral Density Waves ◽  
Mhd Simulations

There is a broad consensus that accretion onto supermassive black holes and consequent jet formation power the observed emission from active galactic nuclei (AGNs). However, there has been less agreement about how jets form in accretion flows, their possible relationship to black hole spin, and how they interact with the surrounding medium. There have also been theoretical concerns about instabilities in standard accretion disk models and lingering discrepancies with observational constraints. Despite seemingly successful applications to X-ray binaries, the standard accretion disk model faces a growing list of observational constraints that challenge its application to AGNs. Theoretical exploration of these questions has become increasingly reliant on numerical simulations owing to the dynamic nature of these flows and the complex interplay between hydrodynamics, magnetic fields, radiation transfer, and curved spacetime. We conclude the following: ▪  The advent of general relativistic magnetohydrodynamics (MHD) simulations has greatly improved our understanding of jet production and its dependence on black hole spin. ▪  Simulation results show both disks and jets are sensitive to the magnetic flux threading the accretion flow as well as possible misalignment between the angular momentum of the accretion flow and the black hole spin. ▪  Radiation MHD simulations are providing new insights into the stability of luminous accretion flows and highlighting the potential importance of radiation viscosity, UV opacity from atoms, and spiral density waves in AGNs.

Elusive accretion discs in low luminosity AGN

2019 ◽  
Vol 15 (S356) ◽  
pp. 97-97
Author(s):  
M. Almudena Prieto ◽  
Juan A. Fernandez-Ontiveros
Keyword(s):  
Black Hole ◽  
Mechanical Energy ◽  
Accretion Discs ◽  
Electromagnetic Spectrum ◽  
True Nature ◽  
Black Hole Spin ◽  
Black Hole Masses ◽  
Very High

AbstractLow luminosity AGN represent the vast majority of the AGN population in the near universe, and still the least conforming class with the standard AGN scenario. Their low luminosity is at odds with their often very high black hole masses and powerful jets. I will review the challenges that parsec-scale observations across the electromagnetic spectrum of some of the nearest ones are opening on the true nature of their emission, their transition from the most luminous to the feeble ones, and their accretion power. The strict limits imposed by these observations on their accretion power are confronted with the high mechanical energy inferred for their jets. Possible scenarios for these nuclei including the extraction of power form the black hole spin are discussed (Prieto et al. 2016; Fernandez-Ontiveros et al. 2019).

scholarly journals Constraint on the black hole spin of M87 from the accretion-jet model

2017 ◽  
Vol 470 (1) ◽  
pp. 612-616 ◽  
Author(s):  
Jianchao Feng ◽  
Qingwen Wu
Keyword(s):  
Black Hole ◽  
Accretion Rate ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Jet Formation ◽  
Accretion Flow ◽  
Hot Plasma ◽  
Spin Parameter ◽  
Jet Power ◽  
Fast Rotating

Abstract The millimetre bump, as found in high-resolution multiwaveband observations of M87 by Prieto et al., most possibly comes from the synchrotron emission of thermal electrons in advection-dominated accretion flow (ADAF). It is possible to constrain the accretion rate near the horizon if both the nuclear millimetre emission and its polarization are produced by the hot plasma in the accretion flow. The jet power of M87 has been extensively explored, which is around $8_{\rm -3}^{+7}\times 10^{42}$ erg s−1 based on the analysis of the X-ray cavity. The black hole (BH) spin can be estimated if the jet power and the accretion rate near the horizon are known. We model the multiwavelength spectral energy distribution (SED) of M87 with a coupled ADAF–jet model surrounding a Kerr BH, where the full set of relativistic hydrodynamical equations of the ADAF are solved. The hybrid jet formation model, as a variant of the Blandford–Znajek model, is used to model the jet power. We find that the SMBH should be fast rotating with a dimensionless spin parameter $a_{*}\simeq 0.98_{\rm -0.02}^{+0.012}$.

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