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Related papers: The Flux Distribution of Sgr A*

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Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, undergoes large-amplitude near-infrared (NIR) flares that can coincide with the continuous rotation of the NIR emission region. One promising explanation…

High Energy Astrophysical Phenomena · Physics 2024-04-18 Arpiar Avetis Grigorian , Jason Dexter

Sgr A*, the putative black hole in our Galactic Center (GC), is extraordinary dim in all frequencies. Apparently the black hole is unable to accrete at the Bondi accretion rate for some reason. Another mystery of Sgr A* is the recently…

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

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

The supermassive black hole Sgr A* at the center of our galaxy produces repeating near-infrared flares that are observed by ground and space based instruments. This activity has been simulated in the past with Magnetically Arrested Disk…

High Energy Astrophysical Phenomena · Physics 2024-09-11 I. Dimitropoulos , A. Nathanail , M. Petropoulou , I. Contopoulos , C. M. Fromm

Sgr A*, the massive black hole at the center of the Galaxy, varies in radio through X-ray emission on hourly time scales. The flare activity is thought to arise from the innermost region of an accretion flow onto Sgr A*. We present…

Astrophysics · Physics 2009-11-13 F. Yusef-Zadeh , M. Wardle , C. Heinke , C. D. Dowell , D. Roberts , F. K. Baganoff , W. D. Cotton

(abridged) We describe highlights of the results of two observing campaigns in 2004 to investigate the correlation of flare activity in Sgr A* in different wavelength regimes, using a total of nine ground and space-based telescopes. We…

Prominent K-shell emission lines of neutral iron (hereafter, FeI-K) and hard-continuum X-rays were found from molecular clouds (MCs) in the Sagittarius B (Sgr B) region with the two separate Suzaku observations in 2005 and 2009. The X-ray…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Masayoshi Nobukawa , Syukyo G. Ryu , Takeshi Go Tsuru , Katsuji Koyama

Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A* exhibits time-variable linear polarization on…

Astrophysics of Galaxies · Physics 2014-11-20 Vincent L. Fish , Sheperd S. Doeleman , Avery E. Broderick , Abraham Loeb , Alan E. E. Rogers

The time-variable emission from the accretion flow of Sgr A*, the supermassive black hole at the Galactic Center, has long been examined in the radio-to-mm, near-infrared (NIR), and X-ray regimes of the electromagnetic spectrum. However,…

We present the result of 6 years monitoring of SgrA*, radio source associated to the supermassive black hole at the centre of the Milky Way. Single dish observations were performed with the Itapetinga radio telescope at 7 mm, and the…

Astrophysics of Galaxies · Physics 2012-11-01 Pedro Paulo B. Beaklini , Zulema Abraham

Starting in 2013 February, Swift has been performing short daily monitoring observations of the G2 gas cloud near Sgr A* with the X-Ray Telescope to determine whether the cloud interaction leads to an increase in the flux from the Galactic…

High Energy Astrophysical Phenomena · Physics 2015-06-15 J. A. Kennea , D. N. Burrows , C. Kouveliotou , D. M. Palmer , E. Gogus , Y. Kaneko , P. A. Evans , N. Degenaar , M. T. Reynolds , J. M. Miller , R. Wijnands , K. Mori , N. Gehrels

We report measurements with the Very Long Baseline Array of the proper motion of Sgr A* relative to two extragalactic radio sources spanning 18 years. The apparent motion of Sgr A* is -6.411 +/- 0.008 mas/yr along the Galactic plane and…

Astrophysics of Galaxies · Physics 2020-04-01 M. J. Reid , A. Brunthaler

We present the first event-horizon-scale images and spatiotemporal analysis of Sgr A* taken with the Event Horizon Telescope in 2017 April at a wavelength of 1.3 mm. Imaging of Sgr A* has been conducted through surveys over a wide range of…

High Energy Astrophysical Phenomena · Physics 2023-11-17 The Event Horizon Telescope Collaboration

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 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

We describe recent results for Sgr A*, M81* and other low luminosity active galactic nuclei. We have conducted linear and circular polarimetry over a frequency range of 1.4 to 230 GHz and detected a variety of phenomena. The polarization…

Astrophysics · Physics 2009-11-07 Geoffrey C. Bower

We have performed monitoring observations of the 3-mm flux density toward the Galactic Center compact radio source Sgr A* with the Australia Telescope Compact Array since 2005 October. Careful calibrations of both elevation-dependent and…

Astrophysics of Galaxies · Physics 2009-07-22 Juan Li , Zhi-Qiang Shen , Atsushi Miyazaki , Lei Huang , R. J. Sault , Makoto Miyoshi , Masato Tsuboi , Takahiro Tsutsumi

We present ALMA observations at 233, 678, and 870 GHz of the Galactic Center black hole, Sagittarius A*. These observations reveal a flat spectrum over this frequency range with spectral index $\alpha \approx -0.3$, where the flux density…

We present a comprehensive data description for Ks-band measurements of Sgr A*. We characterize the statistical properties of the variability of Sgr A* in the near-infrared, which we find to be consistent with a single-state process forming…

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