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Related papers: Properties of accretion shock waves in viscous flo…

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Simulations of hot, pressure supported, tilted black hole accretion flows, in which the angular momentum of the flow is misaligned with the black hole spin axis, can exhibit two non-axisymmetric shock structures in the inner regions of the…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Aleksey Generozov , Omer Blaes , P. Chris Fragile , Ken B. Henisey

Viscous Keplerian discs become sub-Keplerian close to a black hole since they pass through sonic points before entering into it. We study the time evolution of polytropic viscous accretion discs (both in one and two dimensional flows) using…

Astrophysics · Physics 2009-10-30 Giuseppe Lanzafame , D. Molteni , S. K. Chakrabarti

General relativistic, axisymmetric flow of low angular momentum accretion around a Kerr black hole can have certain geometric configuration where the flow is maintained in hydrostatic equilibrium along the vertical direction (direction…

High Energy Astrophysical Phenomena · Physics 2021-01-27 Pratik Tarafdar , Susovan Maity , Tapas K. Das

We investigate the time evolution of the transonic-viscous accretion flow around a non-rotating black hole. The input parameters used for the simulation are obtained from semi-analytical solutions. This code is based on the TVD routine and…

High Energy Astrophysical Phenomena · Physics 2024-01-17 Sanjit Debnath , Indranil Chattopadhyay , Raj Kishor Joshi

We study the two-temperature magnetized advective accretion flow around the Kerr black holes. During accretion, ions are heated up due to viscous dissipation, and when Coulomb coupling becomes effective, they transfer a part of their energy…

High Energy Astrophysical Phenomena · Physics 2020-07-01 Indu K. Dihingia , Santabrata Das , Geethu Prabhakar , Samir Mandal

We study the accretion processes on a black hole by numerical simulation. We use a grid based finite difference code for this purpose. We scan the parameter space spanned by the specific energy and the angular momentum and compare the…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Kinsuk Giri , Sandip K. Chakrabarti , Madan M. Samanta , Dongsu Ryu

It is well known that the rotating inviscid accretion flows with adequate injection parameters around black holes could form shock waves close to the black holes, after the flow passes through the outer sonic point and can be virtually…

Astrophysics · Physics 2015-06-24 T. Okuda , V. Teresi , E. Toscano , D. Molteni

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 carry out the first robust numerical simulation of accretion flows on a weakly magnetized neutron star using Smoothed Particle Hydrodynamics (SPH). We follow the Two-Component Advective Flow (TCAF) paradigm for black holes, and focus…

High Energy Astrophysical Phenomena · Physics 2019-03-20 Ayan Bhattacharjee , Sandip K. Chakrabarti

Most black holes possess accretion disks. Models of such disks inform observations and constrain the properties of the black holes and their surrounding medium. Here, we study isothermal shocks in a thin black hole accretion flow. Modelling…

High Energy Astrophysical Phenomena · Physics 2023-10-27 Eric W. Hester , Geoffrey M. Vasil , Martin Wechselberger

The properties of axisymmetric accretion flows of cold adiabatic gas with zero total energy in the vicinity of a Newtonian point mass are characterized by a single dimensionless parameter, the thickness of incoming flow. In the limit of…

Astrophysics · Physics 2009-10-28 Dongsu Ryu , Garry L. Brown , Jeremiah P. Ostriker , Abraham Loeb

We study the time evolution of a rotating, axisymmetric, viscous accretion flow around black holes using a grid based finite difference method. We use the Shakura-Sunyaev viscosity prescription. However, we compare with the results obtained…

High Energy Astrophysical Phenomena · Physics 2015-06-03 Kinsuk Giri , Sandip K. Chakrabarti

We extend our previous studies of shock waves and shock-free solutions in thin accretion and winds in pseudo-Newtonian geometry to the case when the flow is ``two-dimensional'' and around a ``Kerr black hole''. We present equations for…

Astrophysics · Physics 2016-08-30 S. K. Chakrabarti

We report on the first phase of our study of slightly rotating accretion flows onto black holes. We consider inviscid accretion flows with a spherically symmetric density distribution at the outer boundary, but with spherical symmetry…

Astrophysics · Physics 2009-11-07 D. Proga , M. C. Begelman

We extend our previous numerical simulation of accretion disks with shock waves when cooling effects are also included. We consider bremsstrahlung and other power law processes: $\Lambda \propto T^{\alpha} \rho^2$ to mimic cooling in our…

Astrophysics · Physics 2009-10-28 Diego M. Molteni , H. Sponholz , Sandip K. Chakrabarti

An essential factor in determining the flow characteristics of an accretion flow is its angular momentum. According to the angular momentum of the flow, semi-analytical analysis suggests various types of accretion solutions. It is critical…

High Energy Astrophysical Phenomena · Physics 2024-03-28 Indu K. Dihingia , Yosuke Mizuno

We investigated the instability of advective accretion flow as a consequence of angular momentum transfer in one-dimensional, quasi-spherical transonic accretion flow around a non-rotating black hole. The code is designed to include the…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-09 Seong-Jae Lee , Dongsu Ryu , Indranil Chattopadhyay

We review the current understanding of accretion flows around compact objects with a special emphasis on advective disks. We discuss the influence of the centrifugal pressure supported high density region around compact objects (where…

Astrophysics · Physics 2007-05-23 Sandip K. Chakrabarti

Rotating accretion flow may undergo centrifugal pressure mediated shock transition even in presence of various dissipative processes, such as viscosity and cooling mechanism. The extra thermal gradient force along the vertical direction in…

Astrophysics · Physics 2009-06-23 Santabrata Das , Indranil Chattopadhyay

We present the global structure of magnetized advective accretion flow around the rotating black holes in presence of dissipation. By considering accretion flow to be threaded by toroidal magnetic fields and by assuming synchrotron…

High Energy Astrophysical Phenomena · Physics 2018-08-08 Santabrata Das , Biplob Sarkar