Related papers: Viscous time lags between starburst and AGN activi…
I review accretion and outflow in active galactic nuclei. Accretion appears to occur in a series of very small--scale, chaotic events, whose gas flows have no correlation with the large--scale structure of the galaxy or with each other. The…
Several arguments suggest that stochastic condensation of cold gas and its accretion onto the central supermassive black hole (SMBH) is essential for active galactic nuclei (AGN) feedback to work in the most massive galaxies that lie at the…
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…
Radiation from the blazar class of of active galactic nuclei (AGN) exhibits fast time variability which is usually ascribed to instabilities in the emission region near the central supermassive black hole. The variability time scale is…
The main requirements for fueling an active galactic nucleus and to form massive black holes are reviewed. Low-luminosity AGN can be fueled easily from the local star clusters, near the nucleus, and the various stellar processes are…
We have investigated the gas content of a sample of several hundred AGN host galaxies at z$<$1 and compared it with a sample of inactive galaxies, matched in bins of stellar mass and redshift. Gas masses have been inferred from the dust…
Precise mechanisms by which Active Galactic Nuclei (AGN) receive their gaseous fuel is still a mystery. Here I draw attention to the extra ordinary star formation event that took place in the central ~ 0.5 parsec of our Galaxy. The most…
We assess the potential of nuclear starburst disks to obscure the Seyfert-like AGN that dominate the hard X-ray background at z~1. Over 1200 starburst disk models, based on the theory developed by Thompson et al., are calculated for five…
There is growing evidence for star formation inside outflows of active galactic nuclei (AGNs). The formed stars are injected into bulges and give rise to perturbation of bulges. In this paper, we investigate the issues of non-rotating,…
We present a model that explains some extreme variability phenomena observed in active galactic nuclei (AGN). In this model, an orbiting companion interacts with the accretion disk surrounding the central supermassive black hole (SMBH).…
Dynamical mechanisms are essential to exchange angular momentum in galaxies, drive the gas to the center, and fuel the central super-massive black holes. While at 100pc scale, the gas is sometimes stalled in nuclear rings, recent…
Supermassive Black Holes grow at the center of galaxies in consonance with them. In this review we discuss the mass feeding mechanisms that lead to this growth in Active Galactic Nuclei (AGN), focusing on constraints derived from…
It has been well established in the past decades that the central black hole masses of galaxies correlate with dynamical properties of their harbouring bulges. This notion begs the question of whether there are causal connections between…
Radiation, winds and jets from the active nucleus of a massive galaxy can interact with its interstellar medium leading to ejection or heating of the gas. This can terminate star formation in the galaxy and stifle accretion onto the black…
Molecular gas is the key probe for the complex interaction between the accretion of black holes and star formation of the host galaxy of active galactic nuclei (AGN). The molecular gas discovered around the AGN indicates that this gas is…
For over 60 years, the scientific community has studied actively growing central super-massive black holes (active galactic nuclei -- AGN) but fundamental questions on their genesis remain unanswered. Numerical simulations and theoretical…
We present analytical solutions for winds from galaxies with NFW dark matter halo. We consider winds driven by energy and mass injection from multiple supernovae, as well as momentum injection due to radiation from a central black hole. We…
A fundamental role is attributed to supermassive black holes (SMBH), and the feedback they generate, in the evolution of galaxies. But theoretical models trying to reproduce the relation between the SMBH mass and stellar velocity dispersion…
The processes driving gas accretion on to supermassive black holes (SMBHs) are still poorly understood. Angular momentum conservation prevents gas within $\sim10\,$pc of the black hole from reaching radii $\sim10^{-3}\,$pc where viscous…
Accretion discs around black holes power some of the most luminous objects in the Universe. Discs that are misaligned to the black hole spin can become warped over time by Lense-Thirring precession. Recent work has shown that strongly…