Related papers: Relativistic outflows from a GRMHD mean-field disk…
An optically thin advective accretion disk is crucial for explaining the hard state of black hole sources. Using general relativistic magnetohydrodynamic (GRMHD) simulations, we investigate how a large-scale, strong magnetic field…
The idea that black hole spin is instrumental in the generation of powerful jets in active galactic nuclei and X-ray binaries is arguably the most contentious claim in black hole astrophysics. Because jets are thought to originate in the…
We present a detailed three dimensional magnetohydrodynamic (MHD) simulation describing the inner region of a disk accreting onto a black hole. To avoid the technical complications of general relativity, the dynamics are treated in…
We present the detailed global structure of black hole accretion flows and outflows through newly performed two-dimensional radiation-magnetohydrodynamic simulations. By starting from a torus threaded with weak toroidal magnetic fields and…
We briefly review recent developments in black hole accretion disk theory, placing new emphasis on the vital role played by magnetohydrodynamic (MHD) stresses in transporting angular momentum. The apparent universality of accretion-related…
The existence of the radius of marginal stability means that accretion flows around black holes invariably undergo a transition from a MHD turbulent disk-like flow to an inward plunging flow. We argue that the plunging inflow can greatly…
Understanding the dynamics of low angular momentum accretion flow around black holes (BHs) is essential for probing extreme plasma behavior in strong gravity, where shock formation can naturally produce variability signatures. In this…
We present the results of three-dimensional global resistive magnetohydrodynamic (MHD) simulations of black hole accretion flows. General relativistic effects are simulated by using the pseudo-Newtonian potential. Initial state is an…
We summarize results from a survey of radiation-dominated black hole accretion flows across a wide range of mass accretion rates, as well as two values of black hole spin and initial magnetic field geometry. These models apply an algorithm…
We report new global ideal MHD simulations for thin accretion disks (with thermal scale height H/R=0.1 and 0.05) threaded by net vertical magnetic fields. Our computations span three orders of magnitude in radius, extend all the way to the…
Black-hole accretion systems are known to possess several distinct modes (or spectral states), such as low/hard state, high/soft state, and so on. Since the dynamics of the corresponding flows is distinct, theoretical models were separately…
A magnetic field dynamo in the inner regions of the accretion disk surrounding the supermassive black holes in AGNs may be the mechanism for the generation of magnetic fields in galaxies and in extragalactic space. We argue that the two…
We report results from simulations in general relativity of magnetized disks accreting onto merging black hole binaries, starting from relaxed disk initial data. The simulations feature an effective, rapid radiative cooling scheme as a…
We investigate the extraction of the rotational energy of a black hole under different accreting environment. When the accretion rate is moderate, the accretion disk consists of an outer thin disk and an inner advection-dominated accretion…
In the course of its evolution, a black hole (BH) accretes gas from a wide range of directions. Given a random accretion event, the typical angular momentum of an accretion disc would be tilted by $\sim$60$^\circ$ relative to the BH spin.…
It has long been thought that black hole accretion flows are driven by magnetohydrodynamic (MHD) turbulence, and there are now many general relativistic global simulations illustrating the dynamics of this process. However, many challenges…
We examine mass outflows from a low-angular momentum, viscous, advective, and magnetized accretion disk around a rotating black hole in presence of thermal conduction. We consider the disk is primarily threaded by the toroidal component of…
We report on simulations in general relativity of magnetized disks onto black hole binaries. We vary the binary mass ratio from 1:1 to 1:10 and evolve the systems when they orbit near the binary-disk decoupling radius. We compare (surface)…
It is widely accepted that quasars and other active galactic nuclei (AGN) are powered by accretion of matter onto a central supermassive black hole. While numerical simulations have demonstrated the importance of magnetic fields in…
By studying three-dimensional, radiative, global simulations of sub-Eddington, geometrically thin black hole accretion flows we show that thin disks which are dominated by magnetic pressure are stable against thermal instability. Such disks…