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Supernova 1987A in the Large Magellanic Cloud has proven a unique laboratory to investigate particle acceleration in young supernova remnants. Here we report the first detection of linear polarization of the supernova's synchrotron emission…

High Energy Astrophysical Phenomena · Physics 2018-07-18 Giovanna Zanardo , Lister Staveley-Smith , B. M. Gaensler , Remy Indebetouw , C. -Y. Ng , Mikako Matsuura , A. K. Tzioumis

The properties of blazar variability in the radio band are studied using the unique combination of temporal resolution from single dish monitoring and spatial resolution from VLBA imaging; such measurements, now available in all four Stokes…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Margo F. Aller , Hugh D. Aller , Philip A. Hughes

We present radio continuum light curves of the magnetar SGR J1745$-$2900 and Sgr A* obtained with multi-frequency, multi-epoch Very Large Array observations between 2012 and 2014. During this period, a powerful X-ray outburst from SGR…

High Energy Astrophysical Phenomena · Physics 2015-10-07 F. Yusef-Zadeh , R. Diesing , M. Wardle , L. O. Sjouwerman , M. Royster , W. D. Cotton , D. Roberts , C. Heinke

We present a partial analysis of a multi-wavelength study of the X-ray binary Cir X-1, a system harboring the most relativistic outflow in our galaxy so far. The data were taken (almost) simultaneously in radio and X ray during a survey…

We present the results of a number of high resolution radio observations of the AGN 1156+295. These include multi-epoch and multi-frequency VLBI, VSOP, MERLIN and VLA observations made over a period of 50 months. The 5 GHz MERLIN images…

We report on the analysis of 100 ks INTEGRAL observations of the Galactic microquasar GRS 1915+105. We focus on INTEGRAL Revolution number 48 when the source was found to exhibit a new type of variability as preliminarily reported in…

Fast radio bursts (FRBs) are highly energetic events of short-duration intense radio emission, the origin of which remains elusive till date. Polarization of the FRB signals carry information about the emission source as well as the…

We report the detection of variable linear polarization from Sgr A* at a wavelength of 3.5mm, the longest wavelength yet at which a detection has been made. The mean polarization is 2.1 +/- 0.1% at a position angle of 16 +/- 2 deg with rms…

Fast radio bursts (FRBs) are luminous, dispersed pulses of extra-galactic origin. The physics of the emission mechanism, the progenitor environment, and their origin are unclear. Some repeating FRBs are observed to have frequency-dependent…

We report on full-Stokes L-band observations of 98 MeerKAT calibration sources. Linear polarization is detected in 71 objects above a fractional level of 0.2\%. We identify ten sources with strong fractional linear polarization and low…

Astrophysics of Galaxies · Physics 2024-05-24 A. R. Taylor , L. S. Legodi

We review recent observations of circularly polarized radiation from AGN made with the VLBA and with the ATCA. We also discuss briefly the detections of the Galactic sources Sag A* and SS433. The origin of the circular polarization is still…

Astrophysics · Physics 2007-05-23 John F. C. Wardle , Daniel C. Homan

Evidence of polarized $\gamma$-ray emission ($>$ 50 keV) from Gamma-Ray Bursts (GRBs) has been accumulated in recent years. Measurements have been reported with levels in the range of 30-80\%, typically with limited statistical…

High Energy Astrophysical Phenomena · Physics 2017-02-22 Mark L. McConnell

We investigate circular polarization in pulsar radio emission through simultaneous observations of PSR B1133+16 at two frequencies. In particular, we investigate the association of the handedness of circular polarization with the orthogonal…

Astrophysics · Physics 2009-11-07 A. Karastergiou , S. Johnston , M. Kramer

We present the results of a broadband radio-to-GeV observing campaign organized to get a better understanding of the radiation processes responsible for the $\gamma$-ray flares observed in 3C 279. The total intensity and polarization…

High Energy Astrophysical Phenomena · Physics 2016-10-26 B. Rani , T. P. Krichbaum , S. -S. Lee , K. Sokolovsky , S. Kang , D. -Y. Byun , D. Mosunova , J. A. Zensus

We present data from the first of six monitoring Open Time observations of GRS 1915+105 undertaken with the orbiting INTEGRAL satellite. The source was clearly detected with all three X-ray and gamma-ray instruments on board. GRS 1915+105…

We present the result of multi-wavelength observations of the microquasar GRS 1915+105 in a plateau state with a luminosity of ~7.5x10^{38) erg s-1 (~40% L_Edd), conducted simultaneously with the INTEGRAL and RXTE satellites, the ESO/NTT,…

Aims: We investigate the properties of the polarised radio population in the central 6.5 deg$^{2}$ of the XXL-South field observed at 2.1 GHz using the Australia Telescope Compact Array (ATCA) in 81 pointings with a synthesised beam of FWHM…

Astrophysics of Galaxies · Physics 2019-12-25 R. A. J. Eyles , M. Birkinshaw , V. Smolcic , C. Horellou , M. Huynh , A. Butler , J. Delhaize , C. Vignali , M. Pierre

We report here the detection of circular polarization in the Galactic Center black hole candidate, Sagittarius A*. The detection was made at 4.8 GHz and 8.4 GHz with the Very Large Array. We find that the fractional circular polarization at…

Astrophysics · Physics 2009-10-31 Geoffrey C. Bower , Heino Falcke , Donald C. Backer

We have investigated the radio polarization properties of PSR J1119-6127, a recently discovered young radio pulsar with a large magnetic field. Using pulsar-gated radio imaging data taken at a center frequency of 2496 MHz with the Australia…

Astrophysics · Physics 2009-11-07 Fronefield Crawford , Nathan C. Keim

We report on the discovery of a relativistic iron K\alpha fluorescent emission line in the BeppoSAX spectrum of the microquasar GRS 1915+105, taken on April 19, 1998, when the line was unusually intense. The feature is broad and skewed,…

Astrophysics · Physics 2007-05-23 A. Martocchia , G. Matt , V. Karas , T. Belloni , M. Feroci