Related papers: On the efficient acceleration of clouds in active …
Within the framework of a two-fluid description possible pathways for the generation of fast flows (dynamical as well as steady) in the lower solar atmosphere is established. It is shown that a primary plasma flow (locally sub-Alfv\'enic)…
Flows driven by photons have been studied for almost a century, and a quantitative description of the radiative forces on atoms and ions is important for understanding a wide variety of systems with outflows and accretion disks, such as…
We consider the centrifugal acceleration of charged test particles by rotating magnetospheres which are widely believed to be responsible for the relativistic jet phenomenon in active galactic nuclei (AGN). Based on an analysis of forces…
We demonstrate that the formation of collapsing cores in subcritical clouds is accelerated by nonlinear flows, by performing three-dimensional non-ideal MHD simulations. An initial random supersonic (and trans-Alfvenic) turbulent-like flow…
Both absorption and emission line studies show that cold gas around galaxies is commonly outflowing at speeds of several hundred km$\,\textrm{s}^{-1}$. This observational fact poses a severe challenge to our theoretical models of galaxy…
There are strong suggestions that the disk-like accretion flow onto massive black hole in AGN is disrupted in its innermost part (10-100 Rg), possibly due to the radiation pressure instability. It may form a hot optically thin quasi…
We perform 2D and 3D kinetic simulations of reconnection-mediated turbulent flares in a magnetized electron-positron plasma, with weak and strong radiative cooling. Such flares can be generated around neutron stars and accreting black…
Warm absorber spectra contain bound-bound and bound-free absorption features seen in the X-ray and UV spectra from many active galactic nuclei (AGN). The widths and centroid energies of these features indicate they occur in outflowing gas,…
We perform two-dimensional hydrodynamical simulations of slowly rotating accretion flows in the region of $ 0.01-7\, \mathrm{pc} $ around a supermassive black holes with $ M_\mathrm{BH} = 10^{8} M_{\odot} $. The accretion flow is irradiated…
Our adaptive optics observations of nearby AGN at spatial resolutions as small as 0.085arcsec show strong evidence for recent, but no longer active, nuclear star formation. We begin by describing observations that highlight two contrasting…
Diverging supersonic flows are accelerating, as in the case of a de Laval nozzle, and the same concept has been applied for acceleration of magnetohydrodynamic flows in the universe. Here, we study the dynamics of "non-diverging"…
Active galactic nuclei (AGN) can accelerate protons to energies of $\sim$10-100 TeV, with secondary production of high-energy neutrinos. If the acceleration is driven by magnetized turbulence, the main properties of the resulting proton and…
The variation of an ionizing flux as a mechanism to stimulate the condensation of a diffuse gas is considered. To illustrate this effect, two situations are examined: one on the context of pregalactic conditions, and the other on the…
To investigate the differences in mechanical feedback from radio-loud and radio-quiet Active Galactic Nuclei (AGN) on the host galaxy, we perform 3D AMR hydrodynamic simulations of wide angle, radio-quiet winds with different inclinations…
We investigate the process of rapid star formation quenching in a sample of 12 massive galaxies at intermediate redshift (z~0.6) that host high-velocity ionized gas outflows (v>1000 km/s). We conclude that these fast outflows are most…
(Abridged) We study stability of gas accretion in Active Galactic Nuclei. Our grid based simulations cover a radial range from 0.1 to 200 pc. Here, as in previous studies by our group, we include gas radiative cooling as well as heating by…
The advent of new time domain surveys and the imminent increase in astronomical data expose the shortcomings in traditional time series analysis (such as power spectra analysis) in characterising the abundantly varied, complex and…
While 2% of active galactic nuclei (AGNs) exhibit narrow emission lines with line-of-sight velocities that are significantly offset from the velocity of the host galaxy's stars, the nature of these velocity offsets is unknown. We…
The role of star-formation driven outflows in the obscuration of the central source in the Active Galactic Nuclei (AGN) is discussed. The outflow from a sub-parsec scale accretion disc is numerically modelled for parameters appropriate to…
We propose a nonlinear self-consistent model of the turbulent non-resonant particle acceleration in solar flares. We simulate temporal evolution of the spectra of charged particles accelerated by strong long-wavelength MHD turbulence taking…