相关论文: The Jet in the Galactic Center: An Ideal Laborator…

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 recent detection of significant linear polarization at mm and sub-mm wavelengths in the spectrum of Sgr A* (if confirmed) will be a useful probe of the conditions within several Schwarzschild radii ($r_S$) of the event horizon at the…

Sagittarius A* (Sgr A*), the supermassive black hole at the heart of our galaxy, provides unique opportunities to study black hole accretion, jet formation, and gravitational physics. The rapid structural changes in Sgr A*'s emission pose a…

We present the highest resolution VLBI imaging observations of Sgr A* made at both 7 and 3.5 mm. These data reveal wavelength-dependent intrinsic sizes with an intrinsic emitting region at 3.5 mm of about 1 AU (at a distance of 8 kpc to the…

Submilliarcsecond astrometry and imaging of the black hole Sgr A* at the Galactic Center may become possible in the near future at infrared and submillimetre wavelengths. This resolution is sufficient to observe the silhouette the…

Sagittarius A* (Sgr A*) -- the supermassive black hole (SMBH) in the center of our galaxy -- has been observed in most of the electromagnetic spectrum, from radio to X-rays. Diffuse gamma-ray emission has been observed around Sgr A* and a…

Despite strong physical reasons that they should exist and decades of search, jets from the Galactic Center Black Hole, Sgr A*, have not yet been convincingly detected. Based on high-resolution Very Large Array images and ultra-deep…

(abridged) The connection between black hole, accretion disk, and radio jet can be best constrained by fitting models to observations of nearby low luminosity galactic nuclei, in particular the well studied sources Sgr~A* and M87. There has…

It has been proposed that Very Long Baseline Interferometry (VLBI) at sub-millimeter waves will allow us to image the shadow of the black hole in the center of our Milky Way, Sagittarius A* (Sgr A*), and thereby test basic predictions of…

General relativistic magnetohydrodynamic (GRMHD) simulations of accretion disks and jets associated with supermassive black holes show variability on a wide range of timescales. On timescales comparable to or longer than the gravitational…

Multiwavelength monitoring observations of Sagittarius A* exhibit variability on timescales of minutes to hours, indicating emission regions localized near the event horizon. (Sub)Millimeter-wavelength VLBI is uniquely suited to probe the…

Several stars orbit around a black hole candidate of mass $3.7\times 10^6$ M$_{\odot}$, in the region of the Galactic Center (GC). Looking for General Relativistic (GR) periastron shifts is limited by the existence of a stellar cluster…

The black hole in the center of the Milky Way has been observed and modeled intensely during the last decades. It is also the prime target of a number of new experiments that aim to zoom into the vicinity of its horizon and reveal the inner…

The Galactic center black hole candidate Sgr A* is the best target for studies of low-luminosity accretion physics, including with near-infrared and submillimeter wavelength long baseline interferometry experiments. Here we compare images…

We report the first detection of the Galactic Centre massive black hole, Sgr~A*, in the far infrared. Our measurements were obtained with PACS on board the \emph{Herschel} satellite at $100~\mathrm{\mu m}$ and $160~\mathrm{\mu m}$. While…

We report on new developments in VLBI, with emphasis on experiments performed at the highest frequencies possible to date (so called mm-VLBI). We have observed the nucleus of M 87 (Virgo A) with global VLBI at 3 mm. We show a new image of…

We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A$^*$), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric…

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 summarize the present status of VLBI experiments at 3 mm (86 GHz), 2 mm (129-150 GHz) and 1.3 mm (215-230 GHz). We present and discuss a new 3 mm VLBI map of M87 (Virgo A), which has a spatial resolution of only approx. 20 Schwarzschild…

The Galactic Centre has been studied with the High Energy Stereoscopic System (H.E.S.S.) for over 10 years, revealing a bright, complex gamma-ray morphology. Besides a strong point-like very-high-energy gamma-ray source coincident with the…