Related papers: Impacts of photon bending on observational aspects…
Two component advective flow (TCAF) successfully explains spectral and timing properties of black hole candidates. We study the nature of photon trajectories in the vicinity of a Schwarzschild black hole and incorporate this in predicting…
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…
X-Ray time lag of black hole candidates contains important information regarding the emission geometry. Recently, study of time lags from observational data revealed very intriguing properties. To investigate the real cause of this lag…
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…
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…
Two Component Advective Flow is the only complete solution that incorporates outcomes of actual theoretical solutions to explain spectral and timing properties of radiation emitted from the vicinity of black holes. It redefined the subject…
Outflows are common in many astrophysical systems. In the Two Component Advective Flow ({\fontfamily{qcr}\selectfont TCAF}) paradigm which is essentially a generalized Bondi flow including rotation, viscosity and cooling effects, the…
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…
We carry out a time dependent numerical simulation where both the hydrodynamics and the radiative transfer are coupled together. We consider a two-component accretion flow in which the Keplerian disk is immersed inside an accreting low…
We carry out a series of numerical simulations of viscous accretion flows having a reasonable spatial distribution of the viscosity parameter. We add the power-law cooling throughout the flow. We show that, in agreement with the theoretical…
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…
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 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…
Since black holes are `black', methods of their identification must necessarily be indirect. Due to very special boundary condition on the horizon, the advective flow behaves in a particular way, which includes formation of centrifugal…
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…
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…
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…
Optical field fluctuations in self-defocusing media can be described in terms of sound waves in a 2D photon-fluid. It is shown that, while the background fluid couples with the usual flat metric, sound-like waves experience an effective…
In this paper, we investigate the gravitational lensing properties of magnetically charged black holes within the framework of nonlinear electrodynamics. We derive the deflection angle and examine the influence of the nonlinear…
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…