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Related papers: Non-thermal Emission in Sagittarius B?

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We describe the results of a radio continuum survey of the central 4x1deg with the 100 m Green Bank Telescope (GBT) at wavelengths of 3.5, 6, 20, and 90 cm. The 3.5 and 6 cm surveys are the most sensitive and highest resolution single dish…

Astrophysics · Physics 2009-11-13 C. J. Law , F. Yusef-Zadeh , W. D. Cotton , R. J. Maddalena

Continuum low-frequency radio observations of the Galactic Center reveal the presence of two prominent radio sources, Sgr A East and its surrounding Halo, containing non-thermal particle distributions with power-law indices around 2.5-3.3…

Astrophysics · Physics 2009-10-30 Fulvio Melia , Farhad Yusef-Zadeh , Marco Fatuzzo

We report the discovery of a transient radio source 2.7 arcsec (0.1 pc projected distance) South of the Galactic Center massive black hole, Sagittarius A*. The source flared with a peak of at least 80 mJy in March 2004. The source was…

We report here multi-epoch, multi-frequency observations of the circular polarization in Sagittarius A*, the compact radio source in the Galactic Center. Data taken from the VLA archive indicate that the fractional circular polarization at…

Astrophysics · Physics 2009-11-07 Geoffrey C. Bower , Heino Falcke , Robert J. Sault , Donald C. Backer

Sagittarius B2 (Sgr B2) is a giant molecular cloud complex in the central molecular zone of our Galaxy hosting several sites of high-mass star formation. The two main centers of activity are Sgr B2(M) and Sgr B2(N), which contain 27 and 20…

Astrophysics of Galaxies · Physics 2023-08-23 T. Möller , P. Schilke , Á. Sánchez-Monge , A. Schmiedeke , F. Meng

Radio continuum and radio recombination line observations of the inner degree of the galactic center reveal a rich collection of thermal and nonthermal radio structures: (a) A network of linear filaments that are oriented perpendicular to…

Astrophysics of Galaxies · Physics 2024-07-01 F. Yusef-Zadeh

Using the Mopra telescope, we have undertaken a 3-mm spectral-line imaging survey of a 5 x 5 arcmin^2 area around Sgr B2. We covered almost the complete spectral the range from 81.7 to 113.5 GHz, with 2.2 MHz wide spectral channels or ~ 6…

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

We present new multi-frequency radio continuum imaging of the dwarf starburst galaxy NGC 625 obtained with the Very Large Array. Data at 20, 6, and 3.6 cm reveal global continuum emission dominated by free-free emission, with only mild…

Astrophysics · Physics 2009-11-10 John M. Cannon , Evan D. Skillman

We present low frequency wide band observations (300-500 MHz) of the star forming complex G351.7-1.2 using upgraded Giant Metrewave Radio Telescope (uGMRT), India. Combining this with the optical, infrared and submillimeter data, we analyse…

Astrophysics of Galaxies · Physics 2018-11-28 V. S. Veena , S. Vig , B. Sebastian , D. V. Lal , A. Tej , S. K. Ghosh

Sagittarius A* is a compact radio source at the Galactic center, powered by accretion of fully ionized plasmas into a supermassive black hole. However, the radio emission cannot be produced through the thermal synchrotron process by a…

High Energy Astrophysical Phenomena · Physics 2009-04-02 Kyle W. Martin , Siming Liu , Chris Fragile , Cong Yu , Chris L. Fryer

We made a 100 ks observation of the Sagittarius (Sgr) B1 region at (l, b) = (0.5, -0.1) near to the Galactic center (GC) with the Suzaku/XIS. Emission lines of S XV, Fe I, Fe XXV, and Fe XXVI were clearly detected in the spectrum. We found…

We have undertaken a spectral-line imaging survey of a 6 x 6 arcmin^2 area around Sgr B2 near the centre of the Galaxy, in the range from 30 to 50 GHz, using the Mopra telescope. The spatial resolution varies from 1.0 to 1.4 arcmin and the…

Astrophysics of Galaxies · Physics 2015-05-20 P. A. Jones , M. G. Burton , N. F. H. Tothill , M. R. Cunningham

Sagittarius A* exhibits regular variability in its multiwavelength emission, including daily X-ray flares and roughly continuous near-infrared (NIR) flickering. The origin of this variability is still ambiguous since both inverse Compton…

Radio and $\gamma$-ray measurements of large lobes of several radio galaxies provide adequate basis for determining whether emission in these widely separated spectral regions is largely by energetic electrons. This is very much of interest…

High Energy Astrophysical Phenomena · Physics 2019-09-25 Massimo Persic , Yoel Rephaeli

We exploit the vastly increased sensitivity of the Expanded Very Large Array (EVLA) to study the radio continuum and polarization properties of the post-starburst, dwarf irregular galaxy IC10 at 6 cm, at a linear resolution of ~50 pc. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Volker Heesen , Urvashi Rau , Michael Rupen , Elias Brinks , Deirdre A. Hunter

We present 74 MHz radio continuum observations of the Galactic center region. These measurements show nonthermal radio emission arising from molecular clouds that is unaffected by free-free absorption along the line of sight. We focus on…

Astrophysics of Galaxies · Physics 2019-08-19 F. Yusef-Zadeh , M. Wardle , D. Lis , S. Viti , C. Brogan , E. Chambers , M. Pound , M. Rickert

We present a full analysis of a broadband spectral line survey of Sagittarius B2 (Main), one of the most chemically rich regions in the Galaxy located within the giant molecular cloud complex Sgr B2 in the Central Molecular Zone. Our goal…

Astrophysics of Galaxies · Physics 2021-07-07 T. Möller , P. Schilke , A. Schmiedeke , E. A. Bergin , D. C. Lis , Á. Sánchez-Monge , A. Schwörer , C. Comito

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 report here BIMA array observations of linear polarization in Sagittarius A*, the compact radio source in the Galactic Center. These observations had a resolution of 20 arcsec x 5 arcsec oriented North-South. We do not detect linear or…

Astrophysics · Physics 2009-11-06 Geoffrey C. Bower , Melvyn C. H. Wright , Heino Falcke , Donald C. Backer