相关论文: Evidence for a jet and outflow from Sgr A*: a cont…

We present high-resolution multiwavelength radio continuum images of the region within 150$"$ of Sgr A*, revealing a number of new extended features and stellar sources in this region. First, we detect a continuous 2" east-west ridge of…

The compact radio source Sgr A* is coincident with a 4 million solar mass black hole at the dynamical center of the Galaxy and is surrounded by dense orbiting ionized and molecular gas. We present high resolution radio continuum images of…

We present 44 and 226 GHz observations of the Galactic center within 20$"$ of Sgr A*. Millimeter continuum emission at 226 GHz is detected from eight stars that have previously been identified at near-IR and radio wavelengths. We also…

Context. The properties of the accretion flow surrounding the supermassive central black hole of the Galaxy, Sgr A*, will be scrutinized by the new-generation instrument GRAVITY and the Event Horizon Telescope (EHT). Developing fast,…

Radio and mm-wavelength observations of Sagittarius A* (Sgr A*), the radio source associated with the supermassive black hole at the center of our Galaxy, show that it behaves as a partially self-absorbed synchrotron-emitting source. The…

The radio source Sagittarius A* (Sgr A*) is believed to be a hot, inhomogeneous, magnetized plasma flowing near the event horizon of the 3 million solar mass black hole at the galactic center. At a distance of 8000 parsecs the black hole…

The preliminary detection of the Galactic Center black hole Sgr A* in X-rays by the Chandra mission, as well as recent mm-VLBI measurements, impose strict constraints on this source. Using a relativistic jet model for Sgr A*, we calculate…

The compact radio source at the center of our Galaxy, Sagittarius A* (Sgr A*), is the subject of intensive study as it provides a close-up view of an accreting supermassive black hole. Sgr A* provides us with a prototype of a low-luminosity…

The black hole at the Galactic Center, Sgr A*, is the prototype of a galactic nucleus at a very low level of activity. Its radio through submm-wave emission is known to come from a region close to the event horizon, however, the source of…

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…

Recent observations of the radio and NIR source Sgr A* reinforce the interpretation of the Galactic Center as a scaled down version of an AGN. The discovery of an elongated structure at 43 GHz and increasing evidence for the presence of an…

Despite significant strides made towards understanding accretion, outflow, and emission processes in the Galactic Center supermassive black hole Sagittarius A*, the presence of jets has neither been rejected nor proven. We investigate here…

The source of emission from Sgr A*, the supermassive black hole at the Galactic Center, is still unknown. Flares and data from multiwavelength campaigns provide important clues about the nature of Sgr A* itself. Here we attempt to constrain…

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…

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 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…

In this paper the jet model for the supermassive black hole candidate Sgr A* in the Center of the Galaxy is reviewed. The most recent model, with a reduced set of parameters, is able to account for all major radio properties of the source:…

The Galactic Center supermassive black hole Sagittarius A* (Sgr A*) is one of the most promising targets to study the dynamics of black hole accretion and outflow via direct imaging with very long baseline interferometry (VLBI). At 3.5 mm…

We have used the capabilities of ALMA to probe the ionized gas towards the Galactic center with the H30alpha mm hydrogen recombination line within 30'' of the Galaxy's dynamical center. The observations are made with spatial and spectral…

We observed Sgr A* using the Very Large Array (VLA) and the Giant Metrewave Radio Telescope (GMRT) at multiple cm and mm wavelengths on 17 June 2003. The measured flux densities of Sgr A*, together with those obtained from the Submillimeter…