相关论文: Signatures of an Encounter Between the G2 Cloud an…
A dense ionized cloud of gas has been recently discovered to be moving directly toward the supermassive black hole, Sgr A*, at the Galactic Center. In June 2013, at the pericenter of its highly eccentric orbit, the cloud will be…
The gas cloud G2 falling toward Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, is supposed to provide valuable information on the physics of accretion flows and the environment of the black hole. We…
Gas clouds are present in the Galactic centre, where they orbit around the supermassive black hole. Collisions between these clumps reduce their angular momentum, and as a result some of the clumps are set on a plunging trajectory.…
Measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* at the Galactic Centre is a black hole four million times the mass of the Sun. With the exception of modest X-ray and infrared flares,…
The object G2 was recently discovered descending into the gravitational potential of the supermassive black hole (BH) Sgr A*. We test the photoionized cloud scenario, determine the cloud properties, and estimate the emission during the…
A compact gas cloud G2 is predicted to reach the pericenter of its orbit around the super massive black hole (SMBH) of our galaxy, Sagittarius A* (Sgr A*). This event will give us a rare opportunity to observe the interaction between SMBH…
We carry out a series of simulations of G2-type clouds interacting with the black hole at the galactic center, to determine why no large changes in the luminosity of Sgr A* were seen, and to determine the nature of G2. We measure the…
Galactic nuclei are expected to be densely populated with stellar and intermediate mass black holes. Exploring this population will have important consequences for the observation prospects of gravitational waves as well as understanding…
We present 3D, adaptive mesh refinement simulations of G2, a cloud of gas moving in a highly eccentric orbit towards the galactic center. We assume that G2 originates from a stellar wind interacting with the environment of the Sgr A* black…
The origin, structure and evolution of the small gas cloud, G2, is investigated, that is on an orbit almost straight into the Galactic central supermassive black hole (SMBH). G2 is a sensitive probe of the hot accretion zone of Sgr A*,…
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…
How accretion proceeds around the massive black hole in the Galactic center and other highly sub-Eddington accretors remains poorly understood. The orbit of the S2 star in the Galactic center passes through the accretion disk of the massive…
In 2011, we discovered a compact gas cloud ("G2") with roughly three Earth masses that is falling on a near-radial orbit toward the massive black hole in the Galactic Center. The orbit is well constrained and pericenter passage is predicted…
Galactic Center (GC) molecular cloud Sgr B2 is the best manifestation of an X-ray reflection nebula (XRN) reprocessing a past giant outburst from the supermassive black hole Sgr A*. Alternatively, Sgr B2 could be illuminated by low-energy…
Sgr A* is an ideal target to study low-luminosity accreting systems. It has been recently proposed that properties of the accretion flow around Sgr A* can be probed through its interactions with the stellar wind of nearby massive stars…
An object called G2 was recently discovered moving towards the supermassive black hole in the Galactic Center. G2 emits infrared (IR) lines and continuum, which allows constraining its properties. The question is still unresolved whether G2…
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 study the dynamical evolution of the putative gas clouds G1 and G2 recently discovered in the Galactic center. Following earlier studies suggesting that these two clouds are part of a larger gas streamer, we combine their orbits into a…
We study the dynamical interaction of the G2 cloud with the accretion flow around Sgr A* by means of three-dimensional, hydrodynamic simulations. We show the effects of the rotating accretion flow on the evolution of G2 by projecting the…
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…