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We examine the effect of variable viscosity parameter ($\alpha$) in relativistic, low angular momentum advective accretion flow around rotating black holes. Following the recent simulation studies of magnetohydrodynamic disk that reveal the…

High Energy Astrophysical Phenomena · Physics 2023-12-27 Monu Singh , Santabrata Das

We present global 3D radiation magnetohydrodynamical simulations of accretion onto a 6.62 solar mass black hole with quasi-steady state accretion rates reaching 0.016 to 0.9 times the critical accretion rate, which is defined as the…

High Energy Astrophysical Phenomena · Physics 2023-03-15 Jiahui Huang , Yan-Fei Jiang , Hua Feng , Shane W. Davis , James M. Stone , Matthew J. Middleton

We investigated accretion on to black holes in presence of viscosity and cooling, by employing an equation of state with variable adiabatic index and multi-species fluid. We obtained the expression of generalized Bernoulli parameter which…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Rajiv Kumar , Indranil Chattopadhyay

The Event Horizon Telescope (EHT) has revealed the horizon-scale radiation of Sagittarius A* (Sgr A*), our galaxy's central supermassive black hole, offering a new platform to test gravitational theories. The next step involves studying…

High Energy Astrophysical Phenomena · Physics 2025-01-16 Kotaro Moriyama , Alejandro Cruz-Osorio , Yosuke Mizuno , Indu K. Dihingia , Akhil Uniyal

The present work presents analytically constructed equilibrium structures of charged perfect fluids orbiting Kerr Black holes embedded in an asymptotically uniform magnetic field. Our focus is on the effect of the non-constant angular…

General Relativity and Quantum Cosmology · Physics 2024-09-09 Audrey Trova

The galactic black hole binary systems give an observational template showing how the accretion flow changes as a function of increasing mass accretion rate, or L/L_Edd. These data can be synthetised with theoretical models of the accretion…

Astrophysics · Physics 2009-11-11 Chris Done , Marek Gierlinski

We analyze three-dimensional magnetohydrodynamic (MHD) simulations of a nonradiative accretion flow around a black hole using a pseudo-Newtonian potential. The flow originates from a torus initially centered at 100 gravitational…

Astrophysics · Physics 2009-11-07 John F. Hawley , Steven A. Balbus

Black hole accretion flows can be divided into two broad classes: cold and hot. Cold accretion flows, which consist of cool optically thick gas, are found at relatively high mass accretion rates. Prominent examples are the standard thin…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Feng Yuan , Ramesh Narayan

On the basis of data from an energy-conserving 3D general relativistic MHD simulation, we predict the statistical character of variability in the coronal luminosity from accreting black holes. When the inner boundary of the corona is…

High Energy Astrophysical Phenomena · Physics 2009-09-28 Scott C. Noble , Julian H. Krolik

The accretion of relativistic and non-relativistic fluids into a Reissner-Nordstr\"om black hole is revisited. The position of the critical point, the flow velocity at this point and the accretion rate are only slightly affected with…

General Relativity and Quantum Cosmology · Physics 2011-10-03 J. A. de Freitas Pacheco

High-resolution, multi-wavelength, and time-domain observations of the Galactic centre black hole candidate, Sgr A*, allow for a direct test of contemporary accretion theory. To date, all models have assumed alignment between the accretion…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Jason Dexter , P. Chris Fragile

Understanding the physical structures of the accreated matter very close to the black hole in quasars and active galactic nucleus (AGNs) is an important milestone to constrain the activities occurring in their centers. In this paper, we…

High Energy Astrophysical Phenomena · Physics 2022-05-31 Orhan Donmez , Fatih Dogan , Tugba Sahin

Accretion flows around black holes generally result in mass-outflows that exhibit irregular behavior quite often. Using 2D time-dependent hydrodynamical calculations, we show that the mass-outflow is unstable in the cases of thick accretion…

High Energy Astrophysical Phenomena · Physics 2015-08-19 Toru Okuda , Santabrata Das

Magnetic field behaviour in a spherically-symmetric accretion flow for parameters typical of single black holes in the Galaxy is discussed. It is shown that in the majority of Galaxy volume, accretion onto single stellar-mass black holes…

Astrophysics · Physics 2009-11-10 G. M. Beskin , S. V. Karpov

We present results from two long-duration GRMHD simulations of advection-dominated accretion around a non-spinning black hole. The first simulation was designed to avoid significant accumulation of magnetic flux around the black hole. This…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Ramesh Narayan , Aleksander Sadowski , Robert F. Penna , Akshay K. Kulkarni

In this paper we extend our previous works on spherically symmetric accretion onto black holes and super-spinars to the case in which the fluid has a finite angular momentum initially. We run 2.5D and 3D general relativistic hydrodynamic…

General Relativity and Quantum Cosmology · Physics 2010-12-22 Cosimo Bambi , Naoki Yoshida

We study the formation of the spectra in advection dominated accretion flows (ADAFs) around Kerr black holes. We use a Monte Carlo approach and fully general relativistic treatment to follow the paths of individual photons and model their…

Astrophysics · Physics 2007-05-23 A. Kurpiewski , M. Jaroszynski

In certain scenarios, the accreted angular momentum of plasma onto a black hole could be low; however, how the accretion dynamics depend on the angular momentum content of the plasma is still not fully understood. We present…

High Energy Astrophysical Phenomena · Physics 2025-04-23 Ho-Sang Chan , Prasun Dhang , Jason Dexter , Mitchell C. Begelman

We analyze the properties of a polytropic fluid which is radially accreted into a Schwarzschild black hole. The case where the adiabatic index gamma lies in the range 1 < gamma <= 5/3 has been treated in previous work. In this article we…

General Relativity and Quantum Cosmology · Physics 2016-05-25 Eliana Chaverra , Patryk Mach , Olivier Sarbach

We study the spatial and temporal behavior of fluid in fully three-dimensional, general relativistic, magnetohydrodynamical simulations of both tilted and untilted black hole accretion flows. We uncover characteristically greater…

High Energy Astrophysical Phenomena · Physics 2012-11-16 Ken B. Henisey , Omer M. Blaes , P. Chris Fragile