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We present a new scenario to explain the soft X-ray excess in Active Galactic Nucleus. The magnetic reconnection could happen in a thin layer on the surface of accretion disk. Electrons are accelerated by shock wave and turbulence triggered…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Xiaogu Zhong , Jiancheng Wang

We study a truncated accretion disk using a well-resolved, semi-global magnetohydrodynamic simulation that is evolved for many dynamical times (6096 inner disk orbits). The spectral properties of hard state black hole binary systems and…

High Energy Astrophysical Phenomena · Physics 2018-04-25 J. Drew Hogg , Christopher S. Reynolds

We investigate the properties of a hot accretion flow bathed in a poloidal magnetic field. We consider an axisymmetric viscous resistive flow in the steady state configuration. We assume the dominant mechanism of energy dissipation is due…

High Energy Astrophysical Phenomena · Physics 2017-08-30 Maryam Samadi , Shahram Abbassi

We describe improved modelling of the emission by dust in a toroidal--like structure heated by a central illuminating source within Active Galactic Nuclei (AGN). We chose a simple but realistic torus geometry, a flared disc, and a dust…

Astrophysics · Physics 2009-11-13 J. Fritz , A. Franceschini , E. Hatziminaoglou

We present a broad analysis of X-ray polarimetric observational prospects for radio-quiet active galactic nuclei (AGN), focusing on the role of parsec-scale components. We provide a revision of self-consistent type-1 and type-2 generic AGN…

High Energy Astrophysical Phenomena · Physics 2023-10-25 J. Podgorný , F. Marin , M. Dovčiak

We investigate the properties and evolution of accretion tori formed after the coalescence of two compact objects. At these extreme densities and temperatures, the accreting torus is cooled mainly by neutrino emission produced primarily by…

Astrophysics · Physics 2009-06-23 Agnieszka Janiuk , Ye-Fei Yuan , Rosalba Perna , Tiziana di Matteo

We develop an analytical model for the accretion and gravitational drag on a point mass that moves hypersonically in the midplane of a gaseous disk with a Gaussian vertical density stratification. Such a model is of interest for studying…

Astrophysics of Galaxies · Physics 2015-06-12 J. Cantó , A. Esquivel. F. J. Sánchez-Salcedo , A. C. Raga

We conduct a systematic study of the properties of tilted accretion flows around spinning black holes, covering a range of tilt angles and black hole spins, using the general-relativistic magnetohydrodynamics code Athena++. The same initial…

High Energy Astrophysical Phenomena · Physics 2019-06-25 Christopher J. White , Eliot Quataert , Omer Blaes

Cold steady-state disk wind theory from near Keplerian accretion disks requires a large scale magnetic field at near equipartition strength. However the minimum magnetization has never been tested. We investigate the time evolution of an…

Solar and Stellar Astrophysics · Physics 2015-03-13 Gareth C. Murphy , Jonathan Ferreira , Claudio Zanni

We present new two-fluid models of accretion disks in active galactic nuclei (AGNs) that aim to address the long-standing problem of Toomre instability in AGN outskirts. In the spirit of earlier works by Sirko & Goodman and others, we argue…

High Energy Astrophysical Phenomena · Physics 2022-04-13 Shmuel Gilbaum , Nicholas C. Stone

Aims: We determine the steady-state of an axisymmetric thin accretion disc with an internal dynamo around a magnetised star. Methods: Starting from the vertically integrated equations of magnetohydrodynamics we derive a single ordinary…

High Energy Astrophysical Phenomena · Physics 2010-01-26 Solomon Belay Tessema , Ulf Torkelsson

In this paper we report on the formation of magnetically-levitating accretion disks around supermassive black holes. The structure of these disks is calculated by numerically modelling tidal disruption of magnetized interstellar gas clouds.…

Astrophysics of Galaxies · Physics 2015-06-03 Evghenii Gaburov , Anders Johansen , Yuri Levin

Optical observations cannot resolve the structure of active galactic nuclei (AGN), and a unified model for AGN was inferred mostly from indirect methods. Optical reverberation mapping allowed us to constrain the spatial dimension of the…

High Energy Astrophysical Phenomena · Physics 2017-12-05 P. A. Rojas Lobos , R. W. Goosmann , F. Marin , D. Savić

We investigate the dynamics of the accretion disks of young stars with fossil large-scale magnetic field. The author's magnetohydrodynamic (MHD) model of the accretion disks is generalized to consider the dynamical influence of the magnetic…

Solar and Stellar Astrophysics · Physics 2022-12-28 Sergey A. Khaibrakhmanov , Alexander E. Dudorov

Large scale magnetic field threading an accretion disk is a key ingredient in the jet formation model. The most attractive scenario for the origin of such a large scale field is the advection of the field by the gas in the accretion disk…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Xinwu Cao , H. C. Spruit

The dynamics of accretion discs around galactic and extragalactic black holes may be influenced by their magnetic field. In this paper we generalise the fully relativistic theory of stationary axisymmetric tori in Kerr metric of Abramowicz…

Astrophysics · Physics 2009-11-11 S. S. Komissarov

The standard general relativistic model of a razor-thin accretion disk around a black hole, developed by Novikov & Thorne (NT) in 1973, assumes the shear stress vanishes at the radius of the innermost stable circular orbit (ISCO) and that,…

High Energy Astrophysical Phenomena · Physics 2015-05-18 Robert F. Penna , Jonathan C. McKinney , Ramesh Narayan , Alexander Tchekhovskoy , Rebecca Shafee , Jeffrey E. McClintock

In accretion disks with large-scale ordered magnetic fields, the magnetorotational instability (MRI) is marginally suppressed, so other processes may drive angular momentum transport leading to accretion. Accretion could then be driven by…

High Energy Astrophysical Phenomena · Physics 2018-05-16 Megan D. Marshall , Mark J. Avara , Jonathan C. McKinney

Neutrino-cooled accretion flow around a black hole, produced by a compact binary merger, is a promising scenario for jet formation and magnetic-driven winds to explain short duration gamma ray bursts (GRBs) central engine and kilonovae…

High Energy Astrophysical Phenomena · Physics 2023-03-06 Fatemeh Hossein Nouri , Agnieszka Janiuk

We describe a complete volume limited sample of nearby active galaxies selected by their 14-195keV luminosity, and outline its rationale for studying the mechanisms regulating gas inflow and outflow. We describe also a complementary sample…

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