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Related papers: The Galactic Centre region

200 papers

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

We describe the results of a mJy-sensitivity, VLA survey of roughly 1 square degree near the Galactic center at 6 and 20 cm. Catalogs of compact and filamentary structures are given and compared to previous surveys of the region. Eight of…

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

Results are presented of a new VLA-ROSAT study that probes the magnetic field strength and distribution over a sample of 16 ``normal'' low redshift (z < 0.1) galaxy clusters. The clusters span two orders of magnitude in X-ray luminosity,…

Astrophysics · Physics 2009-10-31 T. E. Clarke , P. P. Kronberg , H. Boehringer

The recent detection of significant linear polarization at mm and sub-mm wavelengths in the spectrum of Sgr A* (if confirmed) will be a useful probe of the conditions within several Schwarzschild radii ($r_S$) of the event horizon at the…

Astrophysics · Physics 2009-10-31 Fulvio Melia , Siming Liu , Robert Coker

Faraday rotation of radio source polarization provides a measure of the integrated magnetic field along the observational lines of sight. We compare a new, large sample of Faraday rotation measures (RMs) of polarized extragalactic sources…

Astrophysics · Physics 2009-11-13 Yongzhong Xu , Philipp P. Kronberg , Salman Habib , Quentin W. Dufton

The scattering diameters of Sgr A* and several nearby OH masers (~ 1" at 1 GHz) indicate that a region of enhanced scattering is along the line of sight to the Galactic center. We combine radio-wave scattering data and free-free emission…

Astrophysics · Physics 2009-10-30 T. Joseph W. Lazio , James M. Cordes

We present a study of the rotation measure (RM) obtained from a sample of extra-galactic radio sources either embedded in or seen in projection through a sample of seven southern galaxy clusters (declination less than 30 degrees). We…

Astrophysics · Physics 2007-05-23 M. Johnston-Hollitt , R. D. Ekers

We present new Faraday rotation measures (RMs) for 148 extragalactic radio sources behind the southern Galactic plane (253o < l < 356o, |b| < 1.5o), and use these data in combination with published data to probe the large-scale structure of…

MAXI J1744$-$294, likely a low-mass X-ray binary system, is a Galactic-center transient source, detected at radio and X-ray wavelengths, located approximately $19''$ southeast of Sgr A*. We report the first detection of its variable linear…

Until recently, the strong interstellar scattering observed towards the Galactic center (GC) black hole, Sgr A*, was thought to come from dense gas within the GC region. The pulse broadening towards the transient magnetar SGR J1745-2900…

Astrophysics of Galaxies · Physics 2017-01-25 Egid Sicheneder , Jason Dexter

To search for a signature of an intracluster magnetic field, we compare measurements of Faraday rotation of polarised extragalactic radio sources in the line of sight of galaxy clusters with those outside. We correlated a catalogue of 1383…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-07 Hans Boehringer , Gayoung Chon , Philipp P. Kronberg

We present a polarimetric map of a 20'x20' area toward the Galactic center. The polarization of point sources has been measured in the J, H, and Ks bands using the near-infrared polarimetric camera SIRPOL on the 1.4 m telescope IRSF. One…

New low-frequency 74 and 330 MHz observations of the Galactic center (GC) region reveal the presence of a large-scale ($6\arcdeg\times 2\arcdeg$) diffuse source of nonthermal synchrotron emission. A minimum energy analysis of this emission…

Astrophysics · Physics 2011-07-18 T. N. LaRosa , C. L. Brogan , S. N. Shore , T. J. Lazio , N. E. Kassim , M. E. Nord

Context. The existence of magnetic fields in the circumgalactic medium (CGM) is largely unconstrained. Their detection is important as magnetic fields can have a significant impact on the evolution of the CGM and, in turn, the fields can…

We present high resolution images of the Faraday Rotation Measure (RM) structure of the radio galaxy PKS 1246-410, at the center of the Centaurus cluster. Comparison with Halpha-line and soft X-ray emission reveals a correspondence between…

Astrophysics · Physics 2009-11-13 G. B. Taylor , A. C. Fabian , G. Gentile , S. W. Allen , C. Crawford , J. S. Sanders

The radio transient ASKAP J173608.2-321735, at the position (l,b)= (356.0872,-0.0390), was serendipitously observed by The HI/OH/Recombination Line Survey of the Galactic Center (THOR-GC) at three epochs in March 2020, April 2020 and…

In this paper we present multifrequency VLA observations of the giant radio galaxy 3C 449, obtained with high sensitivity and resolution in total intensity and polarized flux. These images show the source morphology in great detail, in…

Astrophysics · Physics 2016-08-30 L. Feretti , R. Perley , G. Giovannini , H. Andernach

The radio source Sgr A* in the Galactic center emits a polarized spectrum at millimeter and sub-millimeter wavelengths that is strongly suggestive of relativistic disk accretion onto a massive black hole. We use the well-constrained mass of…

Astrophysics · Physics 2009-11-06 Benjamin C. Bromley , Fulvio Melia , Siming Liu

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

Near-infrared polarimetry of point sources reveals the presence of a toroidal magnetic field in the central 20' x 20' region of our Galaxy. Comparing the Stokes parameters between high extinction stars and relatively low extinction ones, we…