Related papers: The X-ray Disk/Wind Degeneracy in AGN
We report on the iron K-alpha line properties of a sample of Seyfert galaxies observed with the XMM-Newton EPIC pn instrument. Using a systematic and uniform analysis, we find that complexity at iron-K is extremely common in the XMM…
Observations of the fluorescent Fe K-alpha emission line from the inner accretion flows of stellar mass black holes in X-ray binaries and supermassive black holes in Active Galactic Nuclei have become an important tool to study the…
We present a study of X-ray ionization of magnetohydrodynamic (MHD) accretion-disk winds in an effort to constrain the physics underlying the highly-ionized ultra-fast outflows (UFOs) inferred by X-ray absorbers often detected in various…
Accretion disks around black holes radiate a significant fraction of the rest mass of the accreting material in the form of thermal radiation from within a few gravitational radii of the black hole ($ r \lesssim 20 G M / c^{2}$). In…
We present new models for illuminated accretion disks, their structure and reprocessed emission. We consider the effects of incident X-rays on the surface of an accretion disk by solving simultaneously the equations of radiative transfer,…
The ultraviolet (UV) bright accretion disc in active galactic nuclei (AGN) should give rise to line driving, producing a powerful wind which may play an important role in AGN feedback as well as in producing structures like the broad line…
The accretion of matter onto black holes and neutron stars often leads to the launching of outflows that can greatly affect the environments surrounding the compact object. In supermassive black holes, these outflows can even be powerful…
Multiple models have been suggested over the years to explain the structure and support of accretion disks around supermassive black holes, from the standard thin thermal-pressure-dominated $\alpha$-disk model to more recent models that…
Despite early theoretical expectations that large-scale, massive outflows would be triggered by accretion onto black holes and neutron stars, their presence was not firmly established until the 2000s. Since then, these accretion disc winds…
We point out that luminous magnetic flares, thought to occur in standard AGN accretion disks, cannot be located much higher than few pressure scale heights above the disk. Using this fact, we estimate the fraction of the disk surface…
We explore consequences of a radiation driven disk wind model for mass outflows from active galactic nuclei (AGN). We performed axisymmetric time-dependent hydrodynamic calculations using the same computational technique as Proga, Stone and…
Active galactic nucleus (AGN) feedback is the process by which supermassive black holes in the centres of galaxies may moderate the growth of their hosts. Gas outflows from supermassive black holes release huge quantities of energy into the…
Reprocessing of primary X-ray emission in the accretion disk of black hole X-ray binaries (BHXRBs) produces the reflection spectrum, with the characteristic Fe K$\alpha$ fluorescence line. Strong low frequency quasi-periodic oscillations…
We present preliminary results of our study of the impact of strong gravity effects on properties of the high energy radiation produced in accretion flows around supermassive black holes. We refine a model of the X-ray emission from a hot…
We calculate the atmospheric structure of an accretion disk around a Kerr black hole and obtain its X-ray spectrum, which exhibits prominent atomic transitions under certain circumstances. The gravitational and Doppler (red)shifts of the C…
We use a combination of radiation hydrodynamics (rad-HD) and photoionization modeling to study line-driven disc winds for a range of black hole masses. We refined previous models by incorporating heating, cooling, and radiation forces from…
Estimating the mass of a supermassive black hole (SMBH) in an active galactic nucleus (AGN) usually relies on the assumption that the broad line region (BLR) is virialized. However, this assumption seems invalid in BLR models that consists…
Uncorrelated variability between direct X-ray continuum and reflection components (including the Fe line, if present) has been reported in many accreting black hole systems, challenging theoretical models of disc reflection. We explore a…
The continuum-fitting method is one of the two most advanced methods of determining the black hole spin in accreting X-ray binary systems. There are, however, still some unresolved issues with the underlying disk models. One of them…
We consider the spectra of Thomson-thick, geometrically-thin accretion discs around Galactic black hole candidates in the reflection model and compute their iron K edges and iron K$\alpha$ lines. We compare the smeared iron K edge profiles…