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Related papers: Resolving Horizon-Scale Dynamics of Sagittarius A*

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Based on Bremer et al. (2011) and Eckart et al. (2012) we report on simultaneous observations and modeling of the millimeter, near-infrared, and X-ray flare emission of the source Sagittarius A* (SgrA*) associated with the super-massive…

The radiative counterpart of the supermassive black hole at the Galactic Centre, Sagittarius A*, displays flaring emission in the X-ray band atop a steady, quiescent level. Flares are also observed in the near-infrared band. The physical…

We explore the connection between black hole shadows, thermodynamic phase structure, and microstructure of charged and rotating black holes within General Relativity and Geometrothermodynamics. Focusing on Reissner-Nordstr\"om and Kerr…

General Relativity and Quantum Cosmology · Physics 2026-05-05 Jose Miguel Ladino , Carlos E. Romero-Figueroa , Hernando Quevedo

The interplay between supermassive black holes (SMBHs) and their environments is believed to command an essential role in galaxy evolution. The majority of these SMBHs are in the radiative inefficient accretion phase where this interplay…

High Energy Astrophysical Phenomena · Physics 2016-12-30 Shawn R. Roberts , Yan-Fei Jiang , Q. Daniel Wang , Jeremiah P. Ostriker

We report on the polarized light curves of the Galactic Center supermassive black hole Sagittarius A*, obtained at millimeter wavelength with the Atacama Large Millimeter/submillimeter Array (ALMA). The observations took place as a part of…

High Energy Astrophysical Phenomena · Physics 2022-09-22 Maciek Wielgus , Monika Moscibrodzka , Jesse Vos , Zachary Gelles , Ivan Marti-Vidal , Joseph Farah , Nicola Marchili , Ciriaco Goddi , Hugo Messias

The emission region and black hole shadow of Sagittarius A*, the supermassive black hole at the Galactic Center, can be probed with millimeter Very Long Baseline Interferometry. Our goal is to probe the geometry of the emitting plasma…

Astrophysics of Galaxies · Physics 2016-03-23 R. Fraga-Encinas , M. Moscibrodzka , C. Brinkerink , H. Falcke

We summarize the current state of polarization observations of Sagittarius A*, the compact radio source and supermassive black hole candidate in the Galactic Center. These observations are providing new tools for understanding accretion…

Astrophysics · Physics 2007-05-23 Geoffrey C. Bower

The advent of the Event Horizon Telescope (EHT), a millimeter-wave very-long baseline interferometric array, has enabled spatially-resolved studies of the sub-horizon-scale structure for a handful of supermassive black holes. Among these,…

High Energy Astrophysical Phenomena · Physics 2014-03-05 Avery E. Broderick , Tim Johannsen , Abraham Loeb , Dimitrios Psaltis

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…

Originally developed to image the shadow region of the central black hole in Sagittarius A* and in the nearby galaxy M87, the Event Horizon Telescope (EHT) provides deep, very high angular resolution data on other AGN sources too. The…

The cores of most galaxies are thought to harbour supermassive black holes, which power galactic nuclei by converting the gravitational energy of accreting matter into radiation (ref 1). Sagittarius A*, the compact source of radio, infrared…

Timing a pulsar orbiting around Sagittarius A* (Sgr A*) can provide us with a unique opportunity of testing gravity theories. We investigate the detectability of a vector charge carried by the Sgr A* black hole (BH) in the bumblebee gravity…

High Energy Astrophysical Phenomena · Physics 2024-05-01 Zexin Hu , Lijing Shao , Rui Xu , Dicong Liang , Zhan-Feng Mai

We report on the submillimeter properties of Sagittarius A* derived from observations with the Submillimeter Array and its polarimeter. We find that the spectrum of Sgr A* between 230 and 690 GHz is slightly decreasing when measured…

Astrophysics · Physics 2009-11-11 Daniel P. Marrone , James M. Moran , Jun-Hui Zhao , Ramprasad Rao

The compact dark objects with very large masses residing at the centres of galaxies are believed to be black holes. Due to the gravitational lensing effect, they would cast a shadow larger than their horizon size over the background, whose…

Astrophysics · Physics 2008-11-26 Lei Huang , Mike Cai , Zhi-Qiang Shen , Feng Yuan

We present the combination of dynamical accretion model based on 3D GRMHD simulations and general relativistic (GR) polarized radiative transfer. We write down the formalism of and perform the GR ray-tracing of cyclo-synchrotron radiation…

High Energy Astrophysical Phenomena · Physics 2009-12-14 Roman V. Shcherbakov , Robert F. Penna

Sgr A*, the supermassive black hole (SMBH) at the center of our Milky Way Galaxy, is known to be a variable source of X-ray, near-infrared (NIR), and submillimeter (submm) radiation and therefore a prime candidate to study the…

In recent years, near-IR and X-ray flares have been detected from the Galaxy's central radio point source, Sagittarius A* (Sgr A*), believed to be a \~3.10^6 solar masses supermassive black hole. In some cases, the transient emission…

Astrophysics · Physics 2009-11-13 Michel Tagger , Fulvio Melia

We have performed monitoring observations of the flux density toward the Galactic center compact radio source, Sagittarius A* (Sgr A*), which is a supermassive black hole, from 1996 to 2005 using the Nobeyama Millimeter Array of the…

The nature of the emission region around Sagittarius A* (Sgr A*), the supermassive black hole at the Galactic Center, remains under debate. A prediction of jet models is that a frequency-dependent shift in the position of the radio core…

High Energy Astrophysical Phenomena · Physics 2026-02-11 R. Fraga-Encinas , M. Moscibrodzka , H. Falcke

Searching for radio pulsars orbiting around the Galactic centre black hole (BH), Sagittarius A$^\star$ (Sgr A$^\star$), represents a holy grail goal for large-area radio telescopes, in particular for the Square Kilometre Array. Follow-up…

High Energy Astrophysical Phenomena · Physics 2026-04-03 Lijing Shao , Zexin Hu