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We present our view of the immediate environment of an astrophysical black hole. We discuss the origin of the electron-positron and electron-proton jet components, and the origin of the large-scale magnetic field. We show how the aberrated…

High Energy Astrophysical Phenomena · Physics 2019-01-11 Ioannis Contopoulos

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…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Ioannis Contopoulos , Antonios Nathanail , Matthaios Katsanikas

We reinvestigate the generation and accumulation of magnetic flux in optically thin accretion flows around active gravitating objects. The source of the magnetic field is the azimuthal electric current associated with the Poynting-Robertson…

We show that the Poynting-Robertson drag effect in an optically thin advection-dominated accretion flow around active gravitating objects generates strong azimuthal electric currents which give rise to astrophysically significant magnetic…

Astrophysics · Physics 2009-10-30 Ioannis Contopoulos , Demosthenes Kazanas

The Poynting-Robertson Cosmic Battery proposes that the innermost part of the accretion disk around a black hole is threaded by a large scale dipolar magnetic field generated in situ, and that the return part of the field diffuses outward…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Ioannis Contopoulos , Demetrios B. Papadopoulos

The mechanism by which outflows and plausible jets are driven from black hole systems, still remains observationally elusive. Notwithstanding, several observational evidences and deeper theoretical insights reveal that accretion and…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Debbijoy Bhattacharya , Shubhrangshu Ghosh , Banibrata Mukhopadhyay

Astrophysical accretion is arguably the most prevalent physical process in the Universe; it occurs during the birth and death of individual stars and plays a pivotal role in the evolution of entire galaxies. Accretion onto a black hole, in…

High Energy Astrophysical Phenomena · Physics 2009-12-09 Peter B. Dobbie , Zdenka Kuncic , Geoffrey V. Bicknell , Raquel Salmeron

Astrophysical disks are likely embedded in an ambient vertical magnetic field. This ambient field is known to drive magneto-rotational turbulence in the disk bulk but is also responsible for the launching of magnetized outflows at the…

High Energy Astrophysical Phenomena · Physics 2021-03-31 J. Jacquemin-Ide , G. Lesur , J. Ferreira

The centre of our Milky Way harbours the closest candidate for a supermassive black hole. The source is thought to be powered by radiatively inefficient accretion of gas from its environment. This form of accretion is a standard mode of…

The large-scale magnetic field threading an accretion disk plays an important role in launching jets/outflows. The field may probably be advected inwards by the plasma in the accretion disk from the ambient environment (interstellar medium…

High Energy Astrophysical Phenomena · Physics 2019-02-27 Jiawen Li , Xinwu Cao

Outflows and convective motions in accretion flows have been intensively discussed recently in the context of advection-dominated accretion flow (ADAF) based on two-dimensional (2D) and three-dimensional (3D) hydrodynamical simulations. We,…

Astrophysics · Physics 2007-05-23 Mami Machida , Ryoji Matsumoto , and Shin Mineshige

Using long-duration general relativistic magnetohydrodynamic simulations of radiatively inefficient accretion discs, the energy, momentum and mass outflow rates from such systems are estimated. Outflows occur via two fairly distinct modes:…

High Energy Astrophysical Phenomena · Physics 2015-06-16 A. Sadowski , R. Narayan , R. Penna , Y. Zhu

We address the role of large scale magnetic stress in the angular momentum transport, as well as the formation of different kinds of magnetic barrier in geometrically thick, optically thin, vertically averaged 1.5-dimensional advective…

High Energy Astrophysical Phenomena · Physics 2019-08-28 Tushar Mondal , Banibrata Mukhopadhyay

The jets observed to emanate from many compact accreting objects may arise from the twisting of the magnetic field threading a differentially rotating accretion disk which acts to magnetically extract angular momentum and energy from the…

High Energy Astrophysical Phenomena · Physics 2009-01-30 R. V. E. Lovelace , M. M. Romanova

The existence of outflow in accretion flows is confirmed by observations and magnetohydrodynamics (MHD) simulations. In this paper, we study outflows of accretion flows in the presence of resistivity and toroidal magnetic field. The…

High Energy Astrophysical Phenomena · Physics 2012-05-11 Kazem Faghei , Azam Mollatayefeh

We investigate how magnetically driven outflows are powered by a rotating, weakly magnetized accretion flow onto a supermassive black hole using axisymmetric magnetohydrodynamic simulations. Our proposed model focuses on the accretion…

Astrophysics of Galaxies · Physics 2022-02-16 Shinsuke Takasao , Yuri Shuto , Keiichi Wada

Active galaxies and quasers are believed to harbour Black Holes at their centers and at the same time produce cosmic radio jets through which immense amount of matter and energy are ejected out of the core of the galaxy. In our work we…

Astrophysics · Physics 2007-05-23 Tapas K. Das

We investigate the dynamics of radiation in an astrophysical accretion disk around a Kerr black hole. The source of the radiation is the accretion disk itself, and not a central object as in previous studies of the Poynting-Robertson…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Leela E. Koutsantoniou , Ioannis Contopoulos

We discuss the importance of large scale strong magnetic field in the removal of angular momentum outward, as well as the possible origin of different kinds of magnetic barrier in advective, geometrically thick, sub-Keplerian accretion…

High Energy Astrophysical Phenomena · Physics 2018-02-28 Tushar Mondal , Banibrata Mukhopadhyay

We suggest a possible mechanism of efficient transport of the large-scale external magnetic flux inward through a turbulent accretion disk. The outward drift by turbulent diffusion which limits the effectiveness of this process is reduced…

Astrophysics · Physics 2009-11-11 Dmitri A. Uzdensky , H. C. Spruit
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