Related papers: Inflow-Outflow Solution with Stellar Winds and Con…
We employ a low angular momentum accretion-outflow scenario to model the flares emanating out from the central region of Sgr A$^*$. The primary donor for matter accreting onto the central SMBH of Sgr A$^*$ is assumed to be the WR star ISR…
We present results of recent observations and theoretical modeling of data from black holes accreting at very low luminosities (L/L_Edd ~ 10^{-8}). We discuss our newly developed time-dependent model for episodic ejection of relativistic…
For most of their lifetime, super-massive black holes (SMBHs) commonly found in galactic nuclei obtain mass from the ambient at a rate well below the Eddington limit, which is mediated by a radiatively inefficient, hot accretion flow. Both…
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,…
(ABRIDGED) We present in detail our new 3D numerical models for the accretion of stellar winds on to Sgr A*. In our most sophisticated models, we put stars on realistic orbits around Sgr A*, include `slow' winds (300 km/s), and account for…
Sgr A* represents a unique laboratory for the detailed study of accretion processes around a low-luminosity supermassive black hole (SMBH). Recent X-ray observations have allowed for spatially resolved modeling of the emission from the…
By solving radiative transfer equations, we examine three-dimensional radiative properties of a magnetohydrodynamic accretion flow model confronting with the observed spectrum of Sgr A*, in the vicinity of supermassive black hole at the…
PAPER WITHDRAWN. The recent detection of Sgr A* in the X-ray band, together with the radio polarization measurements conducted over the past few years, offer the best constraints yet for understanding the nature of the emitting gas within…
The so-called S2 star reached its closest approach to the massive black hole (BH) at around 1500 $R_\mathrm{s}$ in May 2018. It has been proposed that the interaction of its stellar wind with the high-density accretion flow at this distance…
The Galactic Center black hole Sgr A* is the archetypical example of an underfed massive black hole. The extremely low accretion rate can be understood in radiatively inefficient accretion flow models. Testing those models has proven to be…
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…
In accretion-based models for Sgr A* the X-ray, infrared, and millimeter emission arise in a hot, geometrically thick accretion flow close to the black hole. The spectrum and size of the source depend on the black hole mass accretion rate…
The material accreting onto Sgr A* most probably comes from the nearby stars. We analyze the pattern of this flow at distances of a fraction of a parsec and we argue that the net angular momentum of this material is low but non-negligible,…
The recent {\em Chandra} observation of the radio source at the center of our Galaxy, Sgr A$^*$, puts new constraints on its theoretical models. The spectrum is very soft, and the source is rapidly variable. We consider different models to…
The massive black hole in our galactic center, Sgr A*, accretes only a small fraction of the gas available at its Bondi radius. The physical processes determining this accretion rate remain unknown, partly due to a lack of observational…
Sagittarius A* is a compact radio source at the Galactic center, powered by accretion of fully ionized plasmas into a supermassive black hole. However, the radio emission cannot be produced through the thermal synchrotron process by a…
Black hole accretion disks appear to produce invariably plasma outflows that result in blue-shifted absorption features in their spectra. The X-ray absorption-line properties of these outflows are quite diverse, ranging in velocity from…
Recent Chandra observations of an outflowing gas in GRO J1655-40 resulted in a suggestion by Miller et al. (2006) that the wind in this system must be powered by a magnetic process that can also drive accretion through the disk around the…
Motivated by the low-collisionality of gas accreted onto black holes in Sgr A* and other nearby galactic nuclei, we study a family of 2D advective accretion solutions with thermal conduction. While we only impose global inflow, the…
It is thought that many characteristics of the gaseous features within the central parsec of our Galaxy, are associated with the accretion of ambient plasma by a central concentration of mass. Using a 3D hydrodynamical code, we have been…