Related papers: Black Hole Accretion is all about Sub-Keplerian Fl…
Spherical and axisymmetric accretion onto black holes is discussed. Physical processes in various families of solutions are explained and their characteristics are summarized. Recently discovered solutions of axisymmetric flow provide us…
We study the basic properties of accretion flows onto binary supermassive black holes, including the cases in which a circumbinary disk is misaligned with the binary orbital plane, by means of three-dimensional Smoothed Particle…
It is commonly believed that accretion discs are truncated and their inner regions are described by advection dominated accretion flows (ADAFs) in the hard spectral state of black hole X-ray binaries. However, the increasing occurrence of a…
The theory of coronal evaporation predicts the formation of an inner hole in the cool thin accretion disk for mass accretion rates below a certain value (~ 1/50 of the Eddington mass accretion rate) and the sudden disappearance of this hole…
Recent X-ray timing and spectral observations of black hole binaries in outburst have redefined methods for investigating the properties of Galactic black holes and the physics of accretion flows. High-frequency X-ray QPOs in 5 systems…
We investigate advection dominated, transsonic accretion flows in the vicinity of a Kerr black hole. We take into account all relativistic effects in the dynamics of the flow and in the propagation of light. We assume the matter to be…
It has been found that a class of optically-thin two-temperature advection-dominated accretion solutions explains many observations of low-luminosity accreting black holes. Here it is shown that these models give a satisfactory description…
As the luminosity of an accreting black hole drops to a few percent of Eddington, the spectrum switches from the familiar soft state to a hard state that is well-described by a distended and tenuous advection-dominated accretion flow…
The formation of massive black holes and their coevolution with host galaxies are pivotal areas of modern astrophysics. Spherical accretion onto a central point mass serves as a foundational framework in cosmological simulations,…
This paper deals with the dynamical behavior of phantom field near five dimensional charged black hole. We formulate equations of motion for steady-state spherically symmetric flow of phantom fluids. It is found that phantom energy accretes…
We present results from our magnetohydrodynamical simulations of accretion flows onto black holes. Our main focus is the interplay between inflows and related outflows. We consider applications of such flows to the Galatic center and low…
An initially retrograde accretion flow is transformed into a prograde configuration before plunging into the black hole, as a result of the frame-dragging effect induced by the black hole's rotation. The polarized image of a black hole…
(Abridged) We study the dynamical evolution of a stationary, axisymmetric, and perfectly conducting cold accretion disk containing a large-scale magnetic field around a Kerr black hole, trying to understand the relation between accretion…
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…
Accretion onto black holes often leads to the launch of outflows that significantly influence their surrounding environments. The two primary forms of these outflows are X-ray disk winds-hot, ionized gases ejected from the accretion…
The clumpy disc, or inhomogeneous accretion flow, has been proposed to explain the properties of accreting black hole systems. However, the observational evidences remain to be explored. In this work, we calculate the profiles of Fe…
Astronomers have discovered many potential black holes in X-ray binaries and galactic nuclei. These black holes are usually identified by the fact that they are too massive to be neutron stars. Until recently, however, there was no…
Astronomers have discovered many potential black holes in X-ray binaries and galactic nuclei. These black holes are usually identified by the fact that they are too massive to be neutron stars. Until recently, however, there was no…
In astrophysics, accretion is the process by which a massive object acquires matter. The infall leads to the extraction of gravitational energy. Accretion onto dark compact objects such as black holes, neutron stars, and white dwarfs is a…
Accretion disks are observed in young stars, cataclysmic variables, binary X-ray sources et al. Accretion disk theory was first developed as a theory with the local heat balance, where the whole energy produced by a viscous heating was…