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Observations of Sagittarius A* (Sgr A*) in near-infrared (NIR) show irregular flaring activity. Flares coincide with astrometric rotation of brightness centroid and with looping patterns in fractional linear polarization. These signatures…

High Energy Astrophysical Phenomena · Physics 2024-11-27 A. I. Yfantis , M. Wielgus , M. A. Mościbrodzka

Sagittarius A* exhibits frequent flaring activity across the electromagnetic spectrum. Signatures of an orbiting hot spot have been identified in the polarized millimeter wavelength light curves observed with ALMA in 2017 immediately after…

High Energy Astrophysical Phenomena · Physics 2024-03-29 A. I. Yfantis , M. A. Mościbrodzka , M. Wielgus , J. T. Vos , A. Jimenez-Rosales

SgrA$^*$, the supermassive black hole candidate at the Galactic Center, exhibits flares in the X-ray, NIR, and sub-mm bands that may be interpreted within a hot spot model. Light curves and images of hot spots orbiting a black hole are…

General Relativity and Quantum Cosmology · Physics 2015-01-15 Dan Liu , Zilong Li , Cosimo Bambi

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 Event Horizon Telescope has released polarized images of the supermassive black holes Messier 87* (M87*) and Sagittarius A* (Sgr A*) accretion disks. As more images are produced, our understanding of the average polarized emission from…

High Energy Astrophysical Phenomena · Physics 2024-12-10 Daniel C. M. Palumbo

We report on the results of new simulations of near-infrared (NIR) observations of the Sagittarius A* (Sgr A*) counterpart associated with the super-massive black hole at the Galactic Center. The observations have been carried out using the…

Sagittarius A*, the supermassive compact object at the center of the Galaxy, exhibits outbursts in the near infrared and X-ray domains. These flares are likely due to energetic events very close to the central object, on a scale of a few…

Astrophysics · Physics 2011-02-11 N. Hamaus , T. Paumard , T. Müller , S. Gillessen , F. Eisenhauer , S. Trippe , R. Genzel

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

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

Context: We report new polarization measurements of the variable near-infrared emission of the SgrA* counterpart associated with the massive 3--4 10^6 solar masses Black Hole at the Galactic Center. Aims: We investigate the physical…

Astrophysics · Physics 2009-11-11 A. Eckart , R. Schoedel , L. Meyer , S. Trippe , T. Ott , R. Genzel

The Event Horizon Telescope (EHT) Collaboration produced the first image of the apparent shadow of the central black hole of Sagittarius\,A$^*$ (\sgra). \sgra source structure varies significantly on timescales shorter than the duration of…

High Energy Astrophysical Phenomena · Physics 2026-01-26 Braden J. Marazzo-Nowicki , Paul Tiede , Dominic O. Chang , Daniel C. M. Palumbo , Michael D. Johnson

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

The Event Horizon Telescope is a global very-long baseline interferometer capable of probing potential deviations from the Kerr metric, which is believed to provide the unique description of astrophysical black holes. Here we report an…

High Energy Astrophysical Phenomena · Physics 2016-09-02 Tim Johannsen , Carlos Wang , Avery E. Broderick , Sheperd S. Doeleman , Vincent L. Fish , Abraham Loeb , Dimitrios Psaltis

An initial three-station version of the Event Horizon Telescope, a millimeter-wavelength very-long baseline interferometer, has observed Sagittarius A* (Sgr A*) repeatedly from 2007 to 2013, resulting in the measurement of a variety of…

Intense flaring events in the near-infrared and X-ray wavebands of our Galactic Center have been the subject of research for decades. In recent years, the GRAVITY instrument of the Very Large Telescope captured the motion and polarimetric…

High Energy Astrophysical Phenomena · Physics 2024-10-16 Eleni Antonopoulou , Antonios Nathanail

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

As a key science project of the Square Kilometre Array (SKA), the discovery and timing observations of radio pulsars in the Galactic Center would provide high-precision measurements of the spacetime around the supermassive black hole,…

High Energy Astrophysical Phenomena · Physics 2024-12-09 Zexin Hu , Lijing Shao

General relativity makes clear predictions about the spacetime geometry around black holes. In the near future, new facilities will have the capability to explore the metric around SgrA$^*$, the supermassive black hole candidate at the…

General Relativity and Quantum Cosmology · Physics 2014-05-16 Zilong Li , Lingyao Kong , Cosimo Bambi

Future X-ray instrumentation is expected to allow us to significantly improve the constraints derivedfrom the Fe K lines in AGN, such as the black-hole angular momentum (spin) and the inclination angle of the putative accretion disk. We…

Astrophysics of Galaxies · Physics 2014-11-20 K. D. Murphy , T. Yaqoob , M. Dovčiak , V. Karas
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