Related papers: A Generalised Bondi Accretion Model for the Galact…
We present numerical models of the gas dynamics in the inner parsec of the Galactic centre. We follow the gas from its origin as stellar winds of several observed young massive stars, until it is either captured by the central black hole,…
This is a starting point of future work on a more detailed study of early evolutionary phases of galactic nuclei. We put into port the study of the evolution of star accretion onto a supermassive gaseous object in the central region of an…
We model, for the first time, the Bondi-Hoyle accretion of a fluid with velocity gradients onto a Kerr black hole, by numerically solving the fully relativistic hydrodynamics equations. Specifically, we consider a supersonic ideal gas,…
It is believed that most giant elliptical galaxies possess nuclear black holes with masses in excess of $10^8\Msun$. Bondi accretion from the interstellar medium might then be expected to produce quasar-like luminosities from the nuclei of…
We derive an exact solution representing a Bondi-type stationary accretion of a kinetic (Vlasov) gas onto the Kerr black hole. The solution is exact in the sense that relevant physical quantities, such as the particle current density or the…
One of the most active fields of research of modern-day astrophysics is that of massive black hole formation and co-evolution with the host galaxy. In these investigations, ranging from cosmological simulations, to semi-analytical modeling,…
We consider the sample of weakly active galaxies situated in 'Local Universe' collected in the paper of Pellegrini (2005) with inferred accretion efficiencies from $10^{-2}$ to $10^{-7}$. We apply a model of spherically symmetrical Bondi…
This paper presents a study of quasi-steady spherical accretion in the early Universe, before the formation of the first stars and galaxies. The main motivation is to derive the basic formulas that will be used in a companion paper to…
The centre of our Milky Way harbours the closest candidate for a supermassive black hole. The source is thought to be powered by radiatively inefficient accretion of gas from its environment. This form of accretion is a standard mode of…
Previous works show strong winds exist in hot accretion flows around black holes. Those works focus only on the region close to the black hole thus it is unknown whether or where the wind production stops at large radii. In this paper, we…
Spectral and kinematic studies suggest that the nonthermal radio source Sgr A*, located at the center of the Milky Way, is a supermassive compact object with a mass 2-3 million solar masses. Winds from nearby stars, located approximately…
We use Chandra X-ray data and Very Large Array radio observations for a sample of 20 nearby, massive, X-ray bright, early-type galaxies to investigate the relation between the Bondi accretion rates and the mechanical jet powers. We find a…
We study axisymmetric accretion of slowly rotating matter onto a gravitation center. The process of the flow restructuring is presented as the angular velocity of accreting gas approaches the Keplerian velocity. For spherically-symmetric…
Chaotic cold accretion (CCA) profoundly differs from classic black hole accretion models. Using 3D high-resolution simulations, we probe the impact of rotation on the hot and cold accretion flow in a typical massive galaxy. In the hot mode,…
We consider the stability of an accretion disk wind to cloud formation when subject to a central radiation force. For a vertical launch velocity profile that is Keplerian or flatter and the presence of a significant radiation pressure, the…
We perform numerical simulations of clouds in the Galactic Centre (GC) engulfing the nuclear super-massive black hole and show that this mechanism leads to the formation of gaseous accretion discs with properties that are similar to the…
Observational evidence and many numerical simulations show the existence of wind (i.e., uncollimated outflow) in accretion systems of the elliptical galaxy center. One of the primary aims of this study is to investigate the solutions of…
Gas undergoing Bondi accretion onto a supermassive black hole (SMBH) becomes hotter toward smaller radii. We searched for this signature with a Chandra observation of the hot gas in NGC 3115, which optical observations show has a very…
For most of their lives, galaxies are surrounded by large and massive coronae of hot gas, which constitute vast reservoirs for gas accretion. This Chapter describes a mechanism that allows star-forming disc galaxies to extract gas from…
We present a new model for low-luminosity X-ray sources in globular clusters, with L_x < 10^34 erg/s. The model we propose is that of a single neutron star accreting from cluster gas that has accumulated as a natural product of stellar…