Unified description of accretion flows around black holes

Chen, Xingming; Abramowicz, Marek A.; Lasota, Jean–Pierre; Narayan, Ramesh; Yi, Insu

doi:10.1086/187836

Cited by 194 publications

(232 citation statements)

References 10 publications

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“…Chen et al 1995), we found that there are usually three branches of solutions at a given radius: (1) a cold solution, optically thick and geometrically thin, (2) an intermediate solution, and (3) an optically thin and geometrically thicker hot solution. Only the cold and hot solutions are both thermally and viscously stable.…”

Section: Discussionmentioning

confidence: 89%

Relevance of jet emitting disc physics to microquasars: application to Cygnus X-1

Petrucci

Ferreira

Henri

et al. 2010

A&A

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Context. Interpretation of the X-ray spectra of X-ray binaries during their hard states requires a hot, optically thin medium. There are several accretion disc models that account for this aspect. However, none is designed to simultaneously explain powerful jets detected during these states. Aims. A new quasi-Keplerian hot accretion disc solution, a jet emitting disc (JED hereafter), which is part of a global disc-jet MHD structure producing stationary super-alfvénic ejection, is investigated here. Its radiative and energetic properties are then compared to the observational constraints found in Cygnus X-1. Methods. We solve the disc energy equation by balancing the local heating term with advection and cooling by synchrotron, bremsstrahlung, and Comptonization processes. The heating term, disc density, accretion velocity, and magnetic field amplitude were taken from published self-similar models of accretion-ejection structures. Both optically thin and thick regimes are considered in a one-temperature, gas-supported disc. Results. Three branches of solutions are found to be possible at a given radius, but we only investigate the hot, optically thin and geometrically slim solutions. These solutions give simultaneously and consistently the radiative and energetics properties of the discjet system. They are able to reproduce the global accretion-ejection properties of Cygnus X-1 very well, namely its X-ray spectral emission, jet power, and jet velocity. About half of the released accretion power is used to produce two mildly relativistic (v/c 0.5) jets, and for a luminosity of about 1% of the Eddington luminosity, the JED temperature and optical depth are close to what is observed in the hard state of Cygnus X-1. Conclusions. The accretion and ejection properties of JEDs agree with the observations of the prototypical black hole binary Cygnus X-1. The JED solutions are likely to be relevant to the whole class of microquasars.

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Section: Discussionmentioning

confidence: 89%

Relevance of jet emitting disc physics to microquasars: application to Cygnus X-1

Petrucci

Ferreira

Henri

et al. 2010

A&A

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“…The discovery of ADAF solutions (Narayan & Yi 1994, 1995a, 1995bAbramowicz et al 1995;Chen et al 1995;Yuan & Narayan 2014) gave rise to the application of ADAF models in various black hole systems. These systems include the supermassive black hole in the Galactic center, Sagittarius A, low-luminosity AGNs, and black hole XRBs (e.g., Narayan et al 1998;Lasota 1999;Quataert 2001;Ho 2008;Narayan & McClintock 2008;Abramowicz & Fragile 2013).…”

Section: Adaf Disks and The Induction Equationmentioning

confidence: 99%

The Cosmic Battery in Astrophysical Accretion Disks

Contopoulos

Nathanail

Katsanikas

2015

ApJ

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The aberrated radiation pressure at the inner edge of the accretion disk around an astrophysical black hole imparts a relative azimuthal velocity on the electrons with respect to the ions which gives rise to a ring electric current that generates large-scale poloidal magnetic field loops. This is the Cosmic Battery established by Contopoulos and Kazanas in 1998. In the present work we perform realistic numerical simulations of this important astrophysical mechanism in advection-dominated accretion flows, ADAFs. We confirm the original prediction that the inner parts of the loops are continuously advected toward the central black hole and contribute to the growth of the largescale magnetic field, whereas the outer parts of the loops are continuously diffusing outward through the turbulent accretion flow. This process of inward advection of the axial field and outward diffusion of the return field proceeds all the way to equipartition, thus generating astrophysically significant magnetic fields on astrophysically relevant timescales. We confirm that there exists a critical value of the magnetic Prandtl number between unity and 10 in the outer disk above which the Cosmic Battery mechanism is suppressed.

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“…Comparisons of the α-disk model with observations of X-ray binaries and AGN are presented in [39] and [59] [60], respectively. Modern accretion flow models are discussed in [61].…”

Section: Accretion Disksmentioning

confidence: 99%

Atomic X-ray spectroscopy of accreting black holes

Liedahl¹,

Torres²

2005

Can. J. Phys.

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Current astrophysical research suggests that the most persistently luminous objects in the Universe are powered by the flow of matter through accretion disks onto black holes. Accretion disk systems are observed to emit copious radiation across the electromagnetic spectrum, each energy band providing access to rather distinct regimes of physical conditions and geometric scale. X-ray emission probes the innermost regions of the accretion disk, where relativistic effects prevail. While this has been known for decades, it also has been acknowledged that inferring physical conditions in the relativistic regime from the behavior of the X-ray continuum is problematic and not satisfactorily constraining. With the discovery in the 1990s of iron X-ray lines bearing signatures of relativistic distortion came the hope that such emission would more firmly constrain models of disk accretion near black holes, as well as provide observational criteria by which to test general relativity in the strong field limit. Here we provide an introduction to this phenomenon. While the presentation is intended to be primarily tutorial in nature, we aim also to acquaint the reader with trends in current research. To achieve these ends, we present the basic applications of general relativity that pertain to X-ray spectroscopic observations of black hole accretion disk systems, focusing on the Schwarzschild and Kerr solutions to the Einstein field equations. To this we add treatments of the fundamental concepts associated with the theoretical and modeling aspects of accretion disks, as well as relevant topics from observational and theoretical X-ray spectroscopy. PACS Nos.: 32.30. Rj, 32.80.Hd, 95.30.Dr, 95.30.Sf, 95.85.Nv, 97.10.Gz. 97.80.Jp, 98.35.Mp, 98.62.Mw

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Unified description of accretion flows around black holes

Cited by 194 publications

References 10 publications

Relevance of jet emitting disc physics to microquasars: application to Cygnus X-1

Relevance of jet emitting disc physics to microquasars: application to Cygnus X-1

The Cosmic Battery in Astrophysical Accretion Disks

Atomic X-ray spectroscopy of accreting black holes

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