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Related papers: Hot Spots in Sgr A* Accretion Disk: Hydrodynamic I…

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A cold neutral and extremely dim accretion disk may be present as a remnant of a past vigorous activity around the black hole in our Galactic Center (GC). Here we discuss ways to detect such a disk through its interaction with numerous…

Astrophysics · Physics 2009-11-07 Sergei Nayakshin , Rashid Sunyaev , .

The inner few parsecs at the Galactic Center have come under intense scrutiny in recent years, in part due to the exciting broad-band observations of this region, but also because of the growing interest from theorists motivated to study…

Astrophysics · Physics 2009-11-06 Fulvio Melia , Heino Falcke

Due to the short gravitational timescale of Sgr A*, variable emissions near the galactic center are expected in the Very-long-baseline interferometry observations. Phenomenologically, the high-flux variable emissions could be interpreted as…

High Energy Astrophysical Phenomena · Physics 2025-10-10 Qing-Hua Zhu

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…

Astrophysics · Physics 2008-11-26 Scott C. Noble , Po Kin Leung , Charles F. Gammie , Laura G. Book

The hypothesized supermassive black hole in the nucleus of M31 (which we shall hereafter call M31*) has many features in common with Sgr A* at the Galactic Center, yet they differ in several significant and important ways. Though M31* is…

Astrophysics · Physics 2016-08-30 Siming Liu , Fulvio Melia

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

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…

High Energy Astrophysical Phenomena · Physics 2016-05-04 I. M. Christie , M. Petropoulou , P. Mimica , D. Giannios

Sgr A* at the Galactic Center is a puzzling source. It has a mass M=(2.5+/-0.4) x 10^6 solar masses which makes it an excellent black hole candidate. Observations of stellar winds and other gas flows in its vicinity suggest a mass accretion…

Sagittarius A* (Sgr A*) exhibits frequent flaring activity across the electromagnetic spectrum, often associated with a localized region of strong emission, known as a hot spot. We aim to establish an empirical relationship linking key…

High Energy Astrophysical Phenomena · Physics 2026-02-25 A. I. Yfantis , D. C. M. Palumbo , M. Mościbrodzka

By solving radiative transfer equations, we examine three-dimensional radiative properties of a magnetohydrodynamic accretion flow model confronting with the observed spectrum of Sgr A*, in the vicinity of supermassive black hole at the…

Astrophysics of Galaxies · Physics 2015-05-13 Y. Kato , M. Umemura , K. Ohsuga

We aim at modelling small groups of young stars such as IRS 13N, 0.1 pc away from Sgr A*, which is suggested to contain a few embedded massive young stellar objects. We perform hydrodynamical simulations to follow the evolution of molecular…

Astrophysics of Galaxies · Physics 2015-06-17 B. Jalali , I. Pelupessy , A. Eckart , S. Portegies Zwart , N. Sabha , A. Borkar , J. Moultaka , K. Muzic , L. Moser

High resolution observations of Sgr A* have revealed a wide variety of phenomena, ranging from intense rapid flares to quasi-periodic oscillations, making this object an ideal system to study the properties of low luminosity accreting black…

The interaction between the supermassive black hole at the center of the Milky Way, Sagittarius A*, and its accretion disk occasionally produces high-energy flares seen in X-ray, infrared, and radio. One proposed mechanism that produces…

High Energy Astrophysical Phenomena · Physics 2024-04-18 Aviad Levis , Andrew A. Chael , Katherine L. Bouman , Maciek Wielgus , Pratul P. Srinivasan

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…

Astrophysics · Physics 2009-11-10 Sera Markoff

We elucidate the physical origin of the dark spot in the image of supermassive black hole SgrA* presented very recently by the EHT collaboration. It is argued that this dark spot, which is noticeably smaller than the classical black hole…

High Energy Astrophysical Phenomena · Physics 2022-08-24 Vyacheslav I. Dokuchaev

In Sgr A* at the Galactic center, by far the closest and easiest supermassive black hole we can study, the observational evidence is increasingly pointing to the presence of a compact, hot, magnetized disk feeding the accretor. In such…

Astrophysics · Physics 2009-11-13 Gabriel Rockefeller , Christopher L. Fryer , Fulvio Melia

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,…

Astrophysics of Galaxies · Physics 2013-08-20 S. Gillessen , R. Genzel , T. K. Fritz , E. Quataert , C. Alig , A. Burkert , J. Cuadra , F. Eisenhauer , O. Pfuhl , K. Dodds-Eden , C. F. Gammie , T. Ott

High-resolution near infrared observations with GRAVITY instrument have revealed rapid orbital motions of a hot spot around Sgr A*, the supermassive black hole in our Galactic center, during its three bright flares. The projected distances…

High Energy Astrophysical Phenomena · Physics 2023-02-01 Xi Lin , Ya-Ping Li , Feng Yuan

The accretion flow around the Galactic Center black hole Sagittarius A* (Sgr A*) is expected to have an electron temperature that is distinct from the ion temperature, due to weak Coulomb coupling in the low-density plasma. We present four…

High Energy Astrophysical Phenomena · Physics 2018-05-31 Andrew Chael , Michael E. Rowan , Ramesh Narayan , Michael D. Johnson , Lorenzo Sironi

Context. Magnetically arrested disks are among the most suitable candidates for describing the gas accretion and observed emission in the vicinity of supermassive black holes. Aims. This work aims to provide a direct correlation between the…

High Energy Astrophysical Phenomena · Physics 2025-04-02 Eleni Antonopoulou , Argyrios Loules , Antonios Nathanail