Related papers: Current High Energy Emission from Black Holes
We review the current state of understanding how accretion onto a black hole proceeds and what are they key elements needed to form relativistic jets. Since the theoretical progress is severely halted by the lack of deep understanding of…
Combined influence of rotation of a black hole and ambient magnetic fields creates conditions for powerful astrophysical processes of accretion and outflow of matter which are observed in many systems across the range of masses; from…
I consider how physical processes scale over eight orders of magnitude in black hole mass, from stellar masses in gamma-ray bursts (GRB) and black-hole X-ray binaries (BHXRB) to supermassive active galactic nuclei (AGN). Accretion rates…
A brief summary of the properties of astrophysical black holes is presented. Various modes of accretion are distinguished, corresponding to accretion at rates from well below to well above the Eddington rate. The importance of mass loss is…
A model is presented in which the strongest radio-emitting jet outflows are produced in black hole systems when the accretion is a geometrically thick ($H/R \sim 1$) inflow ({\it e.g.}, ADAF, CDAF) {\em and} if the black hole is rotating.…
Wind is believed to be widespread in various black hole accretion flows. However, unlike the wind from thin disks, which have substantial observational evidence, the wind from hot accretion flows is difficult to observe due to the extremely…
Gas supplied conservatively to a black hole at rates well below the Eddington rate may not be able to radiate effectively and the net energy flux, including the energy transported by the viscous torque, is likely to be close to zero at all…
A common consequence of accretion onto black holes is the formation of powerful, relativistic jets that escape the system. In the case of supermassive black holes at the centres of galaxies this has been known for decades, but for…
The observable characteristics of gamma-ray bursts (GRBs) embedded in the accretion disk of active galactic nuclei (AGNs) are mainly determined by the jet propagation within the disk. In the massive collapsar scenario, we consider that the…
We describe global, 3D, time-dependent, non-radiative, general-relativistic, magnetohydrodynamic simulations of accreting black holes (BHs). The simulations are designed to transport a large amount of magnetic flux to the center, more than…
Accreting black holes can release enormous amounts of energy to their surroundings, in various forms. Such feedback may profoundly influence a black hole's environment. After briefly reviewing the possible types of feedback, I focus on the…
A self-similar solution for the 3D axi-symmetric radiative MHD equations, which revisits the formation and acceleration of accretion-powered jets in AGNs and microquasars, is presented. The model relies primarily on electromagnetic…
Disc accretion on to a black hole is often misaligned from its spin axis. If the disc maintains a significant magnetic field normal to its local plane, we show that dipole radiation from Lense-Thirring precessing disc annuli can extract a…
The X-ray and radio flares observed in X-ray binaries and active galactic nuclei (AGN) are attributed to energetic electrons in the plasma ejecta from the accretion flows near the black hole in these systems. It is argued that magnetic…
We develop and calibrate a new method for estimating the gravitational radiation emitted by complex motions of matter sources in the vicinity of black holes. We compute numerically the linearized curvature perturbations induced by matter…
Understanding the physics and geometry of accretion and ejection around super massive black holes (SMBHs) is important to understand the evolution of active galactic nuclei (AGN) and therefore of the large scale structures of the Universe.…
Steady axisymmetric outflows originating at the hot coronal magnetosphere of a Schwarzschild black hole and surrounding accretion disk are studied in the framework of general relativistic magnetohydrodynamics (GRMHD). The assumption of…
A simple look at the steady high-energy Universe reveals a clear correlation with outflows generated around compact objects (winds and jets). In the case of relativistic jets, they are thought to be produced as a consequence of the…
An accretion flow onto a supermassive black hole is the primary process powering quasars. However, a geometry of this flow is not well constrained. Both global MHD simulations and observations suggest that there are several emission…
We model non-thermal emission spectrum of the extremely sub-Eddington X-ray binary system A0620-00. It is believed that this non-thermal emission is produced by a radiatively inefficient "quiescent" accretion onto a stellar-mass black hole…