Related papers: Numerical simulations of cold clumps in the hot ac…
We carried out three-dimensional global resistive magnetohydrodynamic (MHD) simulations of the cooling instability in optically thin hot black hole accretion flows by assuming bremsstrahlung cooling. General relativistic effects are…
We discuss accretion flows on massive black holes in which different elements of the flow (clumps) have velocities that may differ substantially. We estimate the consequence of collisions between these clumps as they come close to the…
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…
We study the time evolution of sub-Keplerian transonic accretion flow onto a non-rotating black hole using a three-dimensional, inviscid hydrodynamics simulation code. Prior two-dimensional simulations show that centrifugal barrier in the…
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…
We report on the fourth phase of our study of slightly rotating accretion flows onto black holes. The main new element of this study is that we used fully three dimensional (3-D) numerical simulations. We consider hydrodynamics of inviscid…
Astrophysical gases such as the interstellar-, circumgalactic- or intracluster-medium are commonly multiphase, which poses the question of the structure of these systems. While there are many known processes leading to fragmentation of cold…
After a star has been tidally disrupted by a black hole, the debris forms an elongated stream. We start by studying the evolution of this gas before its bound part returns to the original stellar pericenter. While the axial motion is…
In the prevailing model of galaxy formation and evolution, the process of gas accretion onto central galaxies undergoes a transition from cold-dominated to hot-dominated modes. This shift occurs when the mass of the parent dark matter halos…
Standard accretion disk theory is formulated which is based on the local heat balance. The energy produced by a turbulent viscous heating is supposed to be emitted to the sides of the disc. Sources of turbulence in the accretion disc are…
We use cosmological SPH simulations to study the kinematic signatures of cool gas accretion onto a pair of well-resolved galaxy halos. Cold-flow streams and gas-rich mergers produce a circum-galactic component of cool gas that generally…
Many galaxy clusters pose a "cooling-flow problem", where the observed X-ray emission from their cores is not accompanied by enough cold gas or star formation. A continuous energy source is required to balance the cooling rate over the…
Abridged: We study the properties of clumps formed in three-dimensional weakly magnetized magneto-hydrodynamic simulations of converging flows in the thermally bistable, warm neutral medium (WNM). We find that: (1) Similarly to the…
The purpose of this paper is to explore the dynamical behaviour of hot accretion flow with thermal conduction. The importance of thermal conduction on hot accretion flow is confirmed by observations of the hot gas that surrounds Sgr A$^*$…
Using two-dimensional simulations of non-radiative viscous rotating black hole accretion flows, we show that the flows with alpha~0.1-0.3 self-organize to form stationary unipolar or bipolar outflows accompanied by global meridional…
I present results from numerical simulations of gas dynamics outside luminous accretion disks in active galactic nuclei. The gas, gravitationally captured by a super massive black hole, can be driven away by the energy and momentum of the…
We study the hydrodynamical evolution of massive accretion disks around black holes, formed when a neutron star is disrupted by a black hole in a binary system. Initial conditions are taken from 3D calculations of coalescing binaries.…
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…
We have systematically studied the effect of the orbital inclination in the outburst evolution of black hole transients. We have included all the systems observed by the Rossi X-ray timing explorer in which the thermal, accretion disc…
We present a new model for the creation of cool cores in rich galaxy clusters within a LambdaCDM cosmological framework using the results from high spatial dynamic range, adaptive mesh hydro/N-body simulations. It is proposed that cores of…