相关论文: Modelling Accretion Disk and Stellar Wind Interact…
We revisit theoretical and observational constraints on geometrically-thin disk accretion in Sagittarius A* (Sgr A*). We show that the combined effects of mass outflows and electron energization in the hot part of the accretion flow can…
The Galactic Centre is a hotbed of astrophysical activity, with the injection of wind material from $\sim$30 massive Wolf-Rayet (WR) stars orbiting within 12 arcsec of the supermassive black hole (SMBH) playing an important role.…
The Galactic center provides a unique laboratory to study the interaction of a supermassive black hole (SMBH) with its gaseous and stellar environment. Simulations to determine the accretion of stellar winds from the surrounding O-stars…
The interplay between supermassive black holes (SMBHs) and their environments is believed to command an essential role in galaxy evolution. The majority of these SMBHs are in the radiative inefficient accretion phase where this interplay…
The observed rotation measures (RMs) towards the galactic centre magnetar and towards Sagittarius A* provide a strong constraint on MHD models of the galactic centre accretion flow, probing distances from the black hole separated by many…
The Galactic centre is a hotbed of astrophysical activity, with the injection of wind material from $\sim$30 massive Wolf-Rayet (WR) stars orbiting within 12" of the super-massive black hole (SMBH) playing an important role. Hydrodynamic…
The reported discovery of a cold (~10$^4$ K) disc-like structure within 0.005 pc around the super-massive black hole at the centre of the Milky Way, Sgr A*, has challenged our understanding of the gas dynamics and thermodynamic state of the…
High-resolution, multi-wavelength, and time-domain observations of the Galactic centre black hole candidate, Sgr A*, allow for a direct test of contemporary accretion theory. To date, all models have assumed alignment between the accretion…
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…
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…
We examine the low angular momentum flow model for Sgr A* using two-dimensional hydrodynamical calculations based on the parameters of the specific angular momentum and total energy estimated in the recent analysis of stellar wind of nearby…
Powerful winds driven by active galactic nuclei (AGN) are often invoked to play a fundamental role in the evolution of both supermassive black holes (SMBHs) and their host galaxies, quenching star formation and explaining the tight…
Our central Galactic supermassive black hole, Sgr A*, exists mostly in a very stable, extremely low-luminosity (~10^{-9} L_Edd), thermal quiescent state, which is interrupted roughly daily by a brief, nonthermal X-ray flare. Because they…
We present 3D general relativistic magnetohydrodynamic (GRMHD) simulations of the accretion flow surrounding Sagittarius A* that are initialized using larger-scale MHD simulations of the $\sim$ 30 Wolf--Rayet (WR) stellar winds in the…
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…
We compare the 230 GHz near-horizon emission from Sagittarius A* to simulations representing three classes of accretion flows. Using the structure function to capture the variability statistics of the light curve, we find a noticeable…
At the center of the Milky Way lurks a unique compact nonthermal radio source, Sgr A*. It is thought to be powered by a 2.6 million solar mass black hole that is accreting the stellar winds from the numerous early-type stars that exist in…
Supergiant X-ray Binaries (SgXB) host a compact object, often a neutron star (NS), orbiting an evolved O/B star. Mass transfer proceeds through the intense line-driven wind of the stellar donor, a fraction of which is captured by the…
Wind-fed models offer a unique way to form predictive models of the accretion flow surrounding Sagittarius A*. We present 3D, wind-fed MHD and GRMHD simulations spanning the entire dynamic range of accretion from parsec scales to the event…
Flux variability is a fundamental channel of information from Sgr A* because of its direct probe of processes occurring within an accretion disk under strong gravity. We present simultaneous IR, X-ray and radio observations of Sgr A* on…