Related papers: Self-consistent dynamical model of the Broad Line …
We present a comprehensive analysis of four near-Eddington black hole accretion models computed by solving the GRMHD equations with full radiation transport. This study focuses on the dynamical effects of magnetic field topology and black…
We develop an analytic, steady-state model for the gas environment in quiescent galactic nuclei. We assume that the mass is constantly supplied by a spherically symmetric distribution of wind emitting stars, and that gravity is solely due…
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…
Geometrically thick accretion flows may be present in black hole X-ray binaries observed in the low/hard state and in low-luminosity active galactic nuclei. Unlike in geometrically thin disks, the angular momentum axis in these sources is…
Strong evidence is emerging that winds can be driven from the central regions of accretion disks in both active galactic nuclei (AGN) and Galactic black hole binaries (GBHBs). Direct evidence for highly-ionized, Compton-thin inner-disk…
Many astrophysical sources, e.g., cataclysmic variables, X-ray binaries, active galactic nuclei, exhibit a wind outflow, when they reveal a multicolor blackbody spectrum, hence harboring a geometrically thin Keplerian accretion disk. Unlike…
Black hole binaries show equatorial disc winds at high luminosities, which apparently disappear during the spectral transition to the low/hard state. This is also where the radio jet appears, motivating speculation that both wind and jet…
A general physical mechanism of the formation of line-driven winds at the vicinity of strong gravitational field sources is investigated in the frame of General Relativity. We argue that gravitational redshifting should be taken into…
I review the distinguishing observational characteristics of active galaxies with double-peaked emission lines and their implications for the nature of the line-emitting region. Since double-peaked lines most likely originate in the outer…
Accretion near black holes (BHs) is multidimensional, with turbulence, resistivity, thermal transport, and dust dynamics all playing essential roles. In cold accretion discs (ADs) or the region of an AD where magnetic fields (MFs) are…
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…
There is a very popular two-zone accretion disk model that the inner part of the non-advective Keplerian disk (Shakura-Sunyaev disk) can produce hot advection-dominated accretion flow, which can generate high energy power-law radiation and…
We have computed line profiles from self-gravitating toroids around black holes. The specific angular momentum of the toroids is assumed to be constant in space. The images of the toroids show peculiar feature in the rear side of the black…
The origin, geometry and kinematics of the broad line region (BLR) gas in quasars and active galactic nuclei (AGN) are uncertain. We demonstrate that clumpy biconical disc winds illuminated by an AGN continuum can produce BLR-like spectra.…
We investigate the dynamics of radiation in an astrophysical accretion disk around a Kerr black hole. The source of the radiation is the accretion disk itself, and not a central object as in previous studies of the Poynting-Robertson…
Broad iron emission lines are observed in many accreting systems from black holes in AGN and X-ray binaries to neutron star low-mass X-ray binaries. The origin of the line broadening is often interpreted as due to dynamical broadening and…
Apart from viewing-dependent obscuration, intrinsic broad-line emission from active galactic nuclei (AGNs) follows an evolutionary sequence: Type $1 \to 1.2/1.5 \to 1.8/1.9 \to 2$ as the accretion rate onto the central black hole is…
The high-energy particle production in the accretion flow onto black holes can be a key physics to explain the high-energy neutrino background. While the single-zone approximation has been commonly adopted in studies of the high-energy…
We investigate accretion onto an isolated black hole from uniform winds. If the winds are directed towards the black hole, then the accretion process can be well described by the classical Bondi-Hoyle Lyttleton or BHL accretion. If the wind…
Recent hard X-ray spectroscopy of active galactic nuclei has strongly suggested that double-peaked, very broad Fe K emission arises from an accretion disk around the central engine. Model fitting of the observed Fe K emission line profile…