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We present the results of a parsec-scale polarization study of three FRI radio galaxies - 3C66B, 3C78 and 3C264 - obtained with the Very Long Baseline Array at 5, 8 and 15 GHz. Parsec-scale polarization has been detected in a large number…

Astrophysics of Galaxies · Physics 2011-02-11 P. Kharb , D. C. Gabuzda , C. P. O'Dea , P. Shastri , S. A. Baum

In this work we interpret and discuss the time variable rotation measure (RM) found, for the first time over a 1-yr period, in the core region of a blazar. These results are based on a one-year, multi-frequency (15, 24, and 43 GHz) Very…

High Energy Astrophysical Phenomena · Physics 2017-10-30 R. Lico , J. L. Gómez , K. Asada , A. Fuentes

We investigate the distribution of Faraday rotation measure (RM) in the M87 jet at arc-second scales by using archival polarimetric VLA data at 8, 15, 22 and 43 GHz. We resolve the structure of the RM in several knots along the jet for the…

High Energy Astrophysical Phenomena · Physics 2016-06-01 Juan-Carlos Algaba , Keiichi Asada , Masanori Nakamura

We study the linear polarization of the radio cores of eight blazars simultaneously at 22, 43, and 86 GHz with observations obtained by the Korean VLBI Network (KVN) in three epochs between late 2016 and early 2017 in the frame of the…

We present sub-milliarcsecond resolution total intensity and linear polarization VLBI images of 3C273, using concurrent 43 and 86 GHz data taken with the Very Long Baseline Array in May 2002. The structure seen in the innermost jet suggest…

Astrophysics · Physics 2009-11-11 Joanne M. Attridge , John F. C. Wardle , Daniel C. Homan

We present new 6 and 20 cm Very Large Array (VLA) observations of polarized continuum emission of roughly 0.5 square degrees of the Galactic center (GC) region. The 6 cm observations detect diffuse linearly-polarized emission throughout the…

Astrophysics of Galaxies · Physics 2015-05-27 C. J. Law , M. A. Brentjens , G. Novak

We have studied Very Long Baseline Array (VLBA) polarimetric observations of 8 sources including quasars and BL Lacs at 12, 15, 22, 24 and 43 GHz and high frequency rotation measure ($RM$) maps are presented. We find typical values for the…

High Energy Astrophysical Phenomena · Physics 2015-06-12 J. C. Algaba

Parsec-scale multi-wavelength VLBA polarization observations can be used to study the magnetic-field structures of Active Galactic Nuclei (AGN) based on Faraday Rotation (FR) gradients. A number of transverse FR gradients have been found,…

Cosmology and Nongalactic Astrophysics · Physics 2009-05-15 Mehreen Mahmud , Denise C. Gabuzda

Radio polarimetric observations of Active Galactic Nuclei can reveal the magnetic field structure in the parsec-scale jets of these sources. We have observed the gamma-ray blazar 3C 273 as part of our multi-frequency survey with the Very…

High Energy Astrophysical Phenomena · Physics 2012-08-09 T. Hovatta , M. L. Lister , M. F. Aller , H. D. Aller , D. C. Homan , Y. Y. Kovalev , A. B Pushkarev , T. Savolainen

We present first results from a multifrequency VLBA observations of 3C273 in 2003. The source was observed simultaneously at 5.0, 8.4, 15.3, 22.2, 43.2 and 86.2 GHz, and from this multifrequency data set, spectra of 16 emission features in…

Astrophysics · Physics 2007-08-02 T. Savolainen , K. Wiik , E. Valtaoja , M. Tornikoski

We report results from a deep polarization imaging of the nearby radio galaxy 3C$\,$84 (NGC$\,$1275). The source was observed with the Global Millimeter VLBI Array (GMVA) at 86$\,$GHz at an ultra-high angular resolution of $50\mu$as…

Using one-dimensional models, we show that a helical magnetic field with an appropriate sign of helicity can compensate the Faraday depolarization resulting from the superposition of Faraday-rotated polarization planes from a spatially…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-23 Axel Brandenburg , Rodion Stepanov

Distributions of Faraday rotation measure (FRM) and the projected magnetic field derived by a 3-dimensional simulation of MHD jets are investigated based on our "sweeping magnetic twist model". FRM and Stokes parameters were calculated to…

Astrophysics · Physics 2009-11-10 H. Kigure , Y. Uchida , M. Nakamura , S. Hirose , R. Cameron

We report on multi-frequency polarimetry Very Long Baseline Interferometry observations of active galactic nuclei using the VLBA. These observations are used to construct images of the Faraday Rotation Measure (RM) in J1613+342, Mrk 501, 3C…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 G. B. Taylor , R. Zavala

Motivated by recent observations that show increasing fractional linear polarization with increasing wavelength in a small number of optically thin jet features, i.e. "inverse depolarization", we present a physical model that can explain…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Daniel C. Homan

Several multi-frequency polarization studies have shown the presence of systematic Faraday Rotation gradients across the parsec-scale jets of Active Galactic Nuclei (AGN), taken to be due to the systematic variation of the line-of-sight…

Astrophysics · Physics 2007-08-03 Mehreen Mahmud , Denise Gabuzda , Vladislavs Bezrukovs

We present 2-4 GHz observations of polarized radio galaxies towards eight fast radio bursts (FRBs), producing grids of Faraday rotation measure (RM) sources with sky densities of 9-28 polarized sources per square degree. Using a Bayesian…

Polarization has proved an invaluable tool for probing magnetic fields in relativistic jets. Maps of the intrinsic polarization vectors have provided the best evidence to date for uniform, toroidally dominated magnetic fields within jets.…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Avery E Broderick , Abraham Loeb

Relatively few Very Long Baseline Interferometry (VLBI) polarization observations have been carried out at 18 cm. The importance of such observations lies in their ability to reveal information about the jet magnetic ({\bf B}) field…

Astrophysics · Physics 2007-08-01 Péter Veres , Denise C. Gabuzda

We have conducted a survey of Faraday rotation in a sample of 191 compact radio-loud AGNs as part of the MOJAVE (Monitoring of Jets in Active galactic nuclei with VLBA Experiments) project. The observations were carried out with the VLBA at…

High Energy Astrophysical Phenomena · Physics 2012-05-03 T. Hovatta , M. L. Lister , M. F. Aller , H. D. Aller , D. C. Homan , Y. Y. Kovalev , A. B. Pushkarev , T. Savolainen