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We report the results of a 15 GHz (2 cm) multi-epoch VLBA program, begun in 1994 to study the outflow in radio jets ejected from quasars and active galaxies. The observed flow of 208 distinct features measured in 110 quasars, active…

We are in the process of obtaining VLBA polarisation data for the 135 MOJAVE-I Active Galactic Nuclei at four wavelengths in the 18-22cm band. These observations will enable studies of the evolution of the intensity and magnetic-field…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-01 Colm Coughlan , Ronan Murphy , Kyle Mc Enery , Heather Patrick , Redmond Hallahan , Denise Gabuzda

We aim to investigate the relationship between radio jet activity on parsec-scales and the characteristics of both the bright active galactic nuclei (AGN) and their broad line regions (BLR). For this purpose, we combine 2cm Very Long…

Astrophysics · Physics 2017-08-23 T. G. Arshakian , V. H. Chavushyan , E. Ros , J. A. Zensus

We present results from the Very Long Baseline Array (VLBA) multi-frequency (1.6, 4.4, 8.6, 22 GHz), high-sensitivity (~25 microJy beam^-1), sub-parsec scale (<1 pc) observations and Spectral Energy Distributions (SEDs) for a sample of 12…

The apparent position of the "core" in a parsec-scale radio jet (a compact, bright emitting region at the narrow end of the jet) depends on the observing frequency, owing to synchrotron self-absorption and external absorption. While…

Astrophysics · Physics 2008-05-16 Y. Y. Kovalev , A. P. Lobanov , A. B. Pushkarev , J. A. Zensus

We discuss acceleration measurements for a large sample of extragalactic radio jets from the MOJAVE program which studies the parsec-scale jet structure and kinematics of a complete, flux-density-limited sample of Active Galactic Nuclei…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-20 D. C. Homan , M. Kadler , K. I. Kellermann , Y. Y. Kovalev , M. L. Lister , E. Ros , T. Savolainen , J. A. Zensus

The idea that systematic Faraday Rotation gradients across the parsec-scale jets of AGNs can reveal the presence of helical magnetic (B) fields has been around since the early 1990s. These gradients are taken to be due to the systematic…

High Energy Astrophysical Phenomena · Physics 2019-08-19 Mehreen Mahmud , Colm P. Coughlan , Eoin Murphy , Denise C. Gabuzda , Redmond Hallahan

We present 1625 new 15 GHz (2 cm) VLBA images of 295 jets associated with active galactic nuclei (AGNs) from the MOJAVE and 2 cm VLBA surveys, spanning observations between 1994 Aug 31 and 2013 Aug 20. For 274 AGNs with at least 5 VLBA…

We report the first detection of linearly polarized emission at an observing wavelength of 350 $\mu$m from the radio-loud Active Galactic Nucleus 3C 279. We conducted polarization observations for 3C 279 using the SHARP polarimeter in the…

We present VLBA observations and a statistical analysis of 5 GHz VLBI polarimetry data from 177 sources in the Caltech-Jodrell Bank flat-spectrum (CJF) survey. The CJF survey, a complete, flux-density-limited sample of 293 extragalactic…

Astrophysics · Physics 2008-11-26 L. K. Pollack , G. B. Taylor , R. T. Zavala

The kinematics of jets in active galactic nuclei (QSOs, BL Lacs, Radio Galaxies and Empty Field objects) on parsec scales is being studied with Very Long Baseline Array observations at 15 GHz of a sample of more than 170 radio sources. More…

Astrophysics · Physics 2007-05-23 E. Ros

A single measurement of linear polarization of a nonthermal source provides direct information about the mean direction and level of ordering of the magnetic field. Monitoring of the polarization in blazars, combined with millimeter-wave…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Alan P. Marscher

The magnetic field plays a significant role in the phenomenon of highly collimated jets of active galactic nuclei (AGN). Relativistic effects prevent the direct reconstruction of the magnetic field direction as transverse to electric…

High Energy Astrophysical Phenomena · Physics 2023-03-01 Marina S. Butuzova , Alexander B. Pushkarev

The fine-scale structure and the kinematics of relativistic active galactic nuclei (AGN) jets have been studied by very-long-baseline interferometry at very high resolutions since 1998 at 2 cm wavelength for a sample of over a hundred radio…

Astrophysics · Physics 2014-11-18 Eduardo Ros

Numerous studies have reported significant displacements in the coordinates of active galactic nuclei between measurements using radio interferometry techniques and those obtained by the Gaia space observatory. There is a consensus that…

Astrophysics of Galaxies · Physics 2024-12-04 Dmitry Blinov , Arina Arshinova

We investigate the temporal variability of polarization of synchrotron radiation from blazar jets. Multiwavelength observations revealed high-amplitude rotations of the electric vector position angle (EVPA), both in the optical and in the…

High Energy Astrophysical Phenomena · Physics 2026-01-13 Filippo Bolis , Emanuele Sobacchi , Fabrizio Tavecchio

We report on an ongoing effort to image active galactic nuclei simultaneously observed at 2.3 and 8.6 GHz in the framework of a long-term VLBI project RDV (Research and Development - VLBA) started in 1994 aiming to observe compact…

Astrophysics · Physics 2008-12-31 A. B. Pushkarev , Y. Y. Kovalev

Global VLBI (EVN+VLBA) polarization observations at 5 and 8.4 GHz of ten high redshift (z > 3) quasars are presented. The core and jet brightness temperatures are found through modelling the self-calibrated uv-data with Gaussian components,…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-13 Shane P. O'Sullivan , Denise C. Gabuzda , Leonid I. Gurvits

We present full-Stokes radio polarization observations of the quasar PKS B2126-158 (z=3.268) from 1 to 10 GHz using the Australia Telescope Compact Array. The source has large fractional circular polarization, m_c \equiv |V|/I, detected at…

High Energy Astrophysical Phenomena · Physics 2015-06-16 S. P. O'Sullivan , N. M. McClure-Griffiths , I. J. Feain , B. M. Gaensler , R. J. Sault

Radio interferometric observations of Active Galactic Nuclei (AGN) jets reveal the significant linear polarization of their synchrotron radiation that changes with frequency due to the Faraday rotation. It is generally assumed that such…

Astrophysics of Galaxies · Physics 2024-11-06 E. Yushkov , I. N. Pashchenko , D. D. Sokoloff , G. Chumarin
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