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Related papers: Radio Linear and Circular Polarization from M81*

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We present total-intensity and linear-polarization observations made with the Very Large Array at $\lambda$20 and 6 cm of a representative sample of 42 radio galaxies and quasars selected from the Molonglo Complete Sample. The sources have…

Astrophysics · Physics 2009-10-31 C. H. Ishwara-Chandra , D. J. Saikia , V. K. Kapahi , P. J. McCarthy

We observed two nearby galaxies with potential or weak indications of nuclear activity, M32 and M81, with the MIRLIN mid-IR camera at N band (10.79 microns). M32 is not detected, but we give detailed measurements of the nucleus of M81. Our…

Astrophysics · Physics 2009-11-06 B. Grossan , V. Gorjian , M. Werner , M. Ressler

We report the presence of a 106-day cycle in the radio variability of Sgr A* based on an analysis of data observed with the Very Large Array (VLA) over the past 20 years. The pulsed signal is most clearly seen at 1.3 cm with a ratio of…

Astrophysics · Physics 2009-10-31 Jun-Hui Zhao , G. C. Bower , W. M. Goss

The center of the Milky Way Galaxy hosts a $\sim$4 million solar mass black hole (Sgr A$^*$) that is currently very quiescent with a luminosity many orders of magnitude below those of active galactic nuclei. Reflection of X-rays from Sgr…

High Energy Astrophysical Phenomena · Physics 2023-08-02 Frédéric Marin , Eugene Churazov , Ildar Khabibullin , Riccardo Ferrazzoli , Laura Di Gesu , Thibault Barnouin , Alessandro Di Marco , Riccardo Middei , Alexey Vikhlinin , Enrico Costa , Paolo Soffitta , Fabio Muleri , Rashid Sunyaev , William Forman , Ralph Kraft , Stefano Bianchi , Immacolata Donnarumma , Pierre-Olivier Petrucci , Teruaki Enoto , Iván Agudo , Lucio A. Antonelli , Matteo Bachetti , Luca Baldini , Wayne H. Baumgartner , Ronaldo Bellazzini , Stephen D. Bongiorno , Raffaella Bonino , Alessandro Brez , Niccolò Bucciantini , Fiamma Capitanio , Simone Castellano , Elisabetta Cavazzuti , Chien-Ting Chen , Stefano Ciprini , Alessandra De Rosa , Ettore Del Monte , Niccolò Di Lalla , Victor Doroshenko , Michal Dovciak , Steven R. Ehlert , Yuri Evangelista , Sergio Fabiani , Javier A. Garcia , Shuichi Gunji , Kiyoshi Hayashida , Jeremy Heyl , Adam Ingram , Wataru Iwakiri , Svetlana G. Jorstad , Philip Kaaret , Vladimir Karas , Takao Kitaguchi , Jeffery J. Kolodziejczak , Henric Krawczynski , Fabio La Monaca , Luca Latronico , Ioannis Liodakis , Simone Maldera , Alberto Manfreda , Andrea Marinucci , Alan P. Marscher , Herman L. Marshall , Francesco Massaro , Giorgio Matt , Ikuyuki Mitsuishi , Tsunefumi Mizuno , Michela Negro , C. -Y. Ng , Stephen L. O'Dell , Nicola Omodei , Chiara Oppedisano , Alessandro Papitto , George G. Pavlov , Abel L. Peirson , Matteo Perri , Melissa Pesce-Rollins , Maura Pilia , Andrea Possenti , Juri Poutanen , Simonetta Puccetti , Brian D. Ramsey , John Rankin , Ajay Ratheesh , Oliver J. Roberts , Roger W. Romani , Carmelo Sgrò , Patrick Slane , Gloria Spandre , Doug Swartz , Toru Tamagawa , Fabrizio Tavecchio , Roberto Taverna , Yuzuru Tawara , Allyn F. Tennant , Nicholas E. Thomas , Francesco Tombesi , Alessio Trois , Sergey S. Tsygankov , Roberto Turolla , Jacco Vink , Martin C. Weisskopf , Kinwah Wu , Fei Xie , Silvia Zane

We present a broadband polarization analysis of 36 discrete polarized radio sources over a very broad, densely-sampled frequency band. Our sample was selected on the basis of polarization behaviour apparent in narrowband archival data at…

High Energy Astrophysical Phenomena · Physics 2016-07-06 C. S. Anderson , B. M. Gaensler , I. J. Feain

We have conducted observations of the nearby (11.46 ly) star system Procyon, using MeerKAT's UHF (544-1087 MHz) receivers. We produce full-Stokes time and frequency integrated continuum images, as well as total intensity time series imaging…

Solar and Stellar Astrophysics · Physics 2024-10-22 Ian Heywood , Andrew P. V. Siemion , Daniel Czech , Steve Ertel , Jamie Drew , Kyran Grattan , Kevin Wagner , S. Pete Worden

Long-term X-ray variability of the low-luminosity active galactic nucleus of M81 was studied, using 16 ASCA observations spanning 5.5 years. The object exhibits a factor three variation over the 5.5 years. The source intensity was…

Astrophysics · Physics 2009-10-31 Naoko Iyomoto , Kazuo Makishima

Multi-frequency, polarimetric VLA observations of the non-thermal filaments (NTF's), G0.08+0.15, and G359.96+0.09, also known as the Northern and Southern Threads are presented at 20, 6, 3.6 and 2 cm, with high enough spatial resolution to…

Astrophysics · Physics 2009-10-31 Cornelia C. Lang , Mark Morris , Luis Echevarria

We present polarization measurements at 8.4, 22, and 43 GHz made with the VLA of a complete sample of extragalactic sources stronger than 1 Jy in the 5-year WMAP catalogue and with declinations north of -34 degrees. The observations were…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-07 N. Jackson , I. W. A. Browne , R. A. Battye , D. Gabuzda , A. C. Taylor

The radio emission from M31 (like HI, CO, FIR and H\alpha) is concentrated in the '10 kpc ring', giving an impressive example that cosmic rays are produced in star-forming regions. M31 and M33 have similar strengths of the total magnetic…

Astrophysics · Physics 2007-05-23 Rainer Beck

We present a 400-800 MHz polarimetric analysis of 128 non-repeating fast radio bursts (FRBs) from the first CHIME/FRB baseband catalog, increasing the total number of FRB sources with polarization properties by a factor of ~3. 89 FRBs have…

We have monitored the polarized radiation of the Type IIb SN 1993J in M81 over a period of 41 days, starting from 7 days after the explosion on 1993 March 27.5 (UT). Our data show clear evidence that the intrinsic continuum polarization of…

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

The low-luminosity active galactic nucleus of M81 has been monitored at centimeter wavelengths since early 1993 as a by-product of radio programs to study the radio emission from Supernova 1993J. The extensive data sets reveal that the…

Astrophysics · Physics 2016-08-16 Luis C. Ho , Schuyler D. Van Dyk , Guy G. Pooley , Richard A. Sramek , Kurt W. Weiler

We report first-epoch circular polarization results for 133 active galactic nuclei in the MOJAVE program to monitor the structure and polarization of a flux limited sample of extra-galactic radio jets with the VLBA at 15 GHz. We found…

Astrophysics · Physics 2008-11-26 D. C. Homan , M. L. Lister

The potential role of magnetic fields and cosmic ray propagation for feedback processes in the early Universe can be probed by studies of local starburst counterparts with an equivalent star-formation rate. Archival data from the WSRT was…

Astrophysics of Galaxies · Physics 2017-10-12 B. Adebahr , M. Krause , U. Klein , M. Wezgowiec , D. J. Bomans , R. -J. Dettmar

We report the analysis of deep radio observations of the interacting galaxy system M51 from the Very Large Array, with the goal of understanding the nature of the population of compact radio sources in nearby spiral galaxies. We detect 107…

Astrophysics · Physics 2008-11-26 L. A. Maddox , J. J. Cowan , R. E. Kilgard , E. Schinnerer , C. J. Stockdale

Fast radio bursts (FRBs) are extra-galactic sources with unknown physical mechanisms. They emit millisecond-duration radio pulses with isotropic equivalent energy of $10^{36}\sim10^{41}$ ergs. This corresponds to a brightness temperature of…

We report on a year-long effort to monitor the central supermassive black hole in M81 in the X-ray and radio bands. Using Chandra and the VLA, we obtained quasi-simultaneous observations of M81* on seven occasions during 2006. The X-ray and…

High Energy Astrophysical Phenomena · Physics 2015-05-19 J. M. Miller , M. Nowak , S. Markoff , M. Rupen , D. Maitra

We present polarization measurements of extragalactic radio sources observed during the Cosmic Microwave Background polarization survey of the Q/U Imaging Experiment (QUIET), operating at 43 GHz (Q-band) and 95 GHz (W-band). We examine…