相关论文: Hydrodynamic Simulation of Two Component Advective…
We carry out numerical simulation of accretion flows around a black hole in presence of both viscous and cooling effects. Instead of using a constant $\alpha$ parameter throughout the simulation grid, we assume that $\alpha$ is maximum on…
Two component advective flows are the most physical accretion disks which arise from theoretical consideration. Since viscosity is the determining factor, we investigate the effects of viscous stresses on accretion flows around a…
In a two component advective flow around a compact object, a high viscosity Keplerian disk is flanked by a low angular momentum and low viscosity flow which forms a centrifugal pressure supported shock wave close to the black hole. The…
A black hole accretion may have both the Keplerian and the sub-Keplerian components. We consider the most general accretion flow configuration, namely, two-component advective flow (TCAF) in which the Keplerian disk is immersed inside a low…
We review the advantages of fitting with a Two Component Advective Flow (TCAF) which uses only four physical parameters. We then present the results of hydrodynamic simulations to highlight the fact that the primary component of a black…
A black hole accretion is necessarily transonic. In presence of sufficiently high viscosity and cooling effects, a low-angular momentum transonic flow can become a standard Keplerian disc except close to the where hole where it must pass…
We study the spectral and timing properties of a two component advective flow (TCAF) around a black hole by numerical simulation. Several cases have been simulated by varying the Keplerian disk rate and the resulting spectra and lightcurves…
We study several Galactic black hole candidates using long-time RXTE/ASM X-ray data to search for telltale signatures of differences in viscous timescales in the two components used in the Two-Component Advective Flow (TCAF) paradigm. In…
Spectral and Temporal properties of black hole candidates can be explained reasonably well using Chakrabarti-Titarchuk solution of two component advective flow (TCAF). This model requires two accretion rates, namely, the Keplerian disk…
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…
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…
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…
Two Component Advective Flow (TCAF) successfully explains the spectral and tem- poral properties of outbursting or persistent sources. Images of static TCAF with Compton cloud or CENtrifugal pressure supported Boundary Layer (CENBOL) due to…
An accretion flow around a black hole has a saddle type sonic point just outside the event horizon to guarantee that the flow enters the black hole supersonically. This feature exclusively present in strong gravity limit makes its marks in…
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…
We investigate the time evolution of sub-Keplerian transonic accretion flow onto a non-rotating black hole using axisymmetric viscous hydrodynamic simulations. We simulate the accretion flow using boundary values from semi-analytical…
The fundamental difference between accretion around black holes and neutron stars is the inner boundary condition, which affects the behavior of matter very close to the compact objects. This leads to formation of additional shocks and…
Numerical, two-dimensional, time-dependent hydrodynamical models of geometrically thick accretion discs around black holes are presented. Accretion flows with non-effective radiation cooling (ADAFs) can be both convectively stable or…
We explore spectral properties of a Two-Component Advective Flow (TCAF) around a neutron star. We compute the effects of thermal Comptonization of soft photons emitted from a Keplerian disc and the boundary layer of the neutron star by the…
We solved analytically viscous two-dimensional (2D) fluid equations for accretion and outflows in spherical polar coordinates ($r, \theta, \phi$) and obtained explicitly flow variables in $r-$ and $\theta -$directions around black holes…