English
Related papers

Related papers: Examining molecular clouds in the Galactic Centre …

200 papers

The massive black hole at the Galactic Centre is known to be variable in radio, millimeter, near-IR and X-rays. We investigate the physical processes responsible for the variable observed emissions from the compact radio source Sgr A*. We…

High Energy Astrophysical Phenomena · Physics 2016-02-05 E. M. Howard

The central 0.1 parsecs of the Milky Way host a supermassive black hole identified with the position of the radio and infrared source Sagittarius A*, a cluster of young, massive stars (the S stars) and various gaseous features. Recently,…

It is widely believed that Sgr A$^*$, located at the center of our Galaxy, is a supermassive black hole. Recent observations of its shadow and long-term monitoring of the S2 star have provided compelling evidence supporting this hypothesis.…

General Relativity and Quantum Cosmology · Physics 2025-11-07 Zhen Li

Studies of the inner few parsecs at the Galactic Centre provide evidence of a supermassive black hole, associated with the unusual, variable radio and infrared source Sgr A*. Our major aim is the study and analysis of the physical processes…

High Energy Astrophysical Phenomena · Physics 2016-02-03 E. M. Howard

In recent years the case for the presence of 3-4 10^6 M_sun black hole in our Galactic Center has gained strength from results of stellar dynamics observations and from the detection of several rapid X-ray and IR flares observed in the…

Astrophysics · Physics 2008-11-26 A. Cadez , M. Calvani , A. Gomboc , U. Kostic

We present the first detailed simulation of the interaction between the supernova explosion that produced Sgr A East and the wind-swept inner ~ 2-pc region at the Galactic center. The passage of the supernova ejecta through this medium…

The center of our galaxy hosts Sagittarius~A*, a supermassive compact object of $\sim 4.3\times 10^6$ solar masses, usually associated with a black hole. Nevertheless, black holes possess a central singularity, considered unphysical, and an…

High Energy Astrophysical Phenomena · Physics 2026-04-29 Nicolas Aimar , João Luís Rosa , Hanna Liis Tamm , Paulo Garcia

Sagittarius A* (Sgr A*) is the central supermassive black hole with the mass $\sim 4\times 10^6 M_{\odot}$ in the Milky Way and stars are orbiting around it. In May 2018, one of the nearest stars to Sgr A* named S0-2/S2 experienced the…

Astrophysics of Galaxies · Physics 2020-06-12 Yohsuke Takamori , Shogo Nishiyama , Takayuki Ohgami , Hiromi Saida , Rio Saitou , Masaaki Takahashi

Over a two year period (1995-1997), we have conducted a diffraction-limited imaging study at 2.2 microns of the inner 6"x6" of the Galaxy's central stellar cluster using the Keck 10-m telescope. The K band images obtained reveal a large…

Astrophysics · Physics 2009-10-30 A. M. Ghez , B. L. Klein , M. Morris , E. E. Becklin

The scattering diameters of Sgr A* and several nearby OH masers (~ 1" at 1 GHz) indicate that a region of enhanced scattering is along the line of sight to the Galactic center. The scattering diameter of an extragalactic source seen through…

Astrophysics · Physics 2009-10-30 T. Joseph W. Lazio , James M. Cordes

Illumination of dense gas in the Central Molecular Zone (CMZ) by powerful X-ray flares from Sgr A* leads to prominent structures in the reflected emission that can be observed long after the end of the flare. By studying this emission we…

High Energy Astrophysical Phenomena · Physics 2017-08-23 E. Churazov , I. Khabibullin , R. Sunyaev , G. Ponti

In this article we summarise and discuss the infrared, radio, and X-ray emission from the supermassive black hole in the Galactic Centre, SgrA*. We include new results from near-infrared polarimetric imaging observations obtained on May…

Astrophysics · Physics 2008-11-26 S. Trippe , T. Paumard , T. Ott , S. Gillessen , F. Eisenhauer , F. Martins , R. Genzel

The black hole in the center of the Galaxy, associated with the compact source Sagittarius A* (Sgr A*), is predicted to cast a shadow upon the emission of the surrounding plasma flow, which encodes the influence of general relativity in the…

We use a model of the molecular gas distribution within ~100 pc from the center of the Milky Way (Kruijssen, Dale & Longmore) to simulate time evolution and polarization properties of the reflected X-ray emission, associated with the past…

High Energy Astrophysical Phenomena · Physics 2017-04-12 E. Churazov , I. Khabibullin , G. Ponti , R. Sunyaev

We present the first spectral energy distributions produced self-consistently by 2.5D general relativistic magneto-hydrodynamical (GRMHD) numerical simulations, where radiative cooling is included in the dynamical calculation. As a case…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Samia Drappeau , Salomé Dibi , Jason Dexter , Sera Markoff , P. Chris Fragile

Aims. We report on simultaneous observations and modeling of mid-infrared (MIR), near-infrared (NIR), and submillimeter (submm) emission of the source Sgr A* associated with the supermassive black hole at the center of our Galaxy. Our goal…

Astrophysics of Galaxies · Physics 2013-01-22 X. Haubois , K. Dodds-Eden , A. Weiss , T. Paumard , G. Perrin , Y. Clénet , S. Gillessen , P. Kervella , F. Eisenhauer , R. Genzel , D. Rouan

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…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Jason Dexter , P. Chris Fragile

This paper reports on the early Chandra view of the Galactic center (GC) activities. The massive black hole Sgr A* is extremely faint, while more bright diffuse X-ray emission is prevailing in the circumnuclear disk. Another high…

Astrophysics · Physics 2007-05-23 Katsuji Koyama

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…

High Energy Astrophysical Phenomena · Physics 2015-06-04 Monika Moscibrodzka , Hotaka Shiokawa , Charles F. Gammie , Joshua C. Dolence