Related papers: On the double natured solutions to the two-tempera…
In the standard thin disc formalism the dimensionless $\alpha$ parameter is usually assumed to be constant. However, there are good theoretical reasons for believing, as well as evidence from simulations, that $\alpha$ is dependent on…
A toy model of a disk undergoing steady state accretion onto a black hole is presented. The disk is in a hydrostatic equilibrium for all radii r > r_{in}, with the inner disk radius located between the marginally stable and marginally bound…
Cold optically thick accretion disks with hot coronae and radial advection have been investigated. Within the framework of $\alpha$-viscosity models, we assume that all the mass accretion and angular momentum transport take place in the…
All high temperature accretion solutions including ADAF are physically thick, so outgoing radiation interacts with the incoming flow, sharing as much or more resemblance with classical spherical accretion flows as with disk flows. We…
We self-consistently estimate the outflow rate from the accretion rates of an accretion disk around a black hole in which both the Keplerian and the sub-Keplerian matter flows simultaneously. While Keplerian matter supplies soft-photons,…
A self-consistent solution for a thin accretion disk with turbulent convection is presented. The disk viscosity and the convective flux are derived from a physical model for turbulence, and expressed in terms of the local physical…
Models of the formation, evolution and photoevaporation of circumstellar disks are an essential ingredient in many theories of the formation of planetary systems. The ratio of disk mass over stellar mass in the circumstellar phase of a disk…
We investigate the thermal stability of optically thin, two-temperature, radiative cooling-dominated accretion disks. Our linear analysis shows that the disk is thermally unstable without magnetic fields, which agrees with previous…
We consider the effects of advection and radial gradients of pressure and radial drift velocity on the structure of accretion disks around black holes with proper description of optically thick/thin transitions. We concentrated our efforts…
We calculate self-consistent models of X-ray irradiated accretion discs in close binary systems. We show that a point X-ray source powered by accretion and located in the disc plane cannot modify the disc structure, mainly because of the…
In the past years, several observations of AGN and X-ray binaries have suggested the existence of a warm T around 0.5-1 keV and optically thick, \tau ~ 10-20, corona covering the inner parts of the accretion disk. These properties are…
We present the two-dimensional inflow-outflow solutions of radiation hydrodynamic (RHD) equations of supercritical accretion flows. Compared with prior studies, we include all components of the viscous stress tensor. We assume steady state…
Accretion disks formed in binary neutron star mergers play a central role in many astrophysical processes of interest, including the launching of relativistic jets or the ejection of neutron-rich matter hosting heavy element…
We consider hot, two-temperature, viscous accretion onto a rotating, unmagnetized neutron star. We assume Coulomb coupling betweenthe protons and electrons, and free-free cooling from the electrons. We show that the accretion flow has an…
We present a self-consistent analytical model for the computation of the physical conditions in a steady quasi-Keplerian accretion disk. The method, based on the thin disk approximation, considers the disk as concentric cylinders in which…
We obtained steady solutions of optically thin, single temperature, magnetized black hole accretion disks assuming thermal bremsstrahlung cooling. Based on the results of 3D MHD simulations of accretion disks, we assumed that the magnetic…
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…
Accretion disk theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was emitted to the sides of the disk. One of the most important new invention of this theory was the…
We present time-dependent simulations of a two-phase accretion flow around a black hole. The accretion flow initially is composed of an optically thick and cool disc close to the midplane, while on top and below the disc there is a hot and…
We present the properties of accretion disk corona (ADC) models, where the radiation field, the temperature, and the total opacity of the corona are determined self-consistently. We use a non-linear Monte Carlo code to perform the…