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With high-sensitivity kiloparsec-scale radio polarimetry, we can examine the jet-medium interactions and get a better understanding of the blazar divide in radio-loud (RL) AGN. We are analyzing the radio polarimetric observations with the…

星系天体物理 · 物理学 2023-04-25 Janhavi Baghel , P. Kharb , Silpa S. , Luis C. Ho , C. M. Harrison

Rotations of the electric vector position angle (EVPA) in blazars are often close to an integral multiple of 180$^\circ$. There are multiple examples of this in the literature, and our analysis here, of the optical polarization data from…

高能天体物理现象 · 物理学 2020-04-22 Marshall H. Cohen , Tuomas Savolainen

Previous research showed most BL Lac objects and some quasars have aligned VLBI-core and optical polarizations, although some of the AGNs also showed no obvious relationship between VLBI-core and optical polarization angles. This may…

宇宙学与河外天体物理 · 物理学 2015-05-30 J. C. Algaba , D. C. Gabuzda , P. S. Smith

We study the optical linear and circular polarisation in the optically-thin regime of the core and jet of M87. Observations were acquired two days before the Event Horizon Telescope (EHT) campaign in early April 2017. A high degree ($\sim…

星系天体物理 · 物理学 2020-06-17 A. Y. Fresco , J. A. Fernández-Ontiveros , M. A. Prieto , J. A. Acosta-Pulido , A. Merloni

Very long baseline interferometric observations of the radio galaxy 3C 120 show a systematic presence of gradients in Faraday rotation and degree of polarization across and along the jet. These are revealed by the passage of multiple…

天体物理学 · 物理学 2008-07-17 J. L. Gomez , I. Agudo , A. P. Marscher , S. G. Jorstad , M. Roca-Sogorb

We present total intensity and linear polarization images of OJ287 at 1.68GHz, obtained through space-based VLBI observations with RadioAstron on April 16, 2016. The observations were conducted using a ground array consisting of the VLBA…

Relativistic jets originating at the center of AGN are embedded in extreme environments with strong magnetic fields and high particle densities, which makes them a fundamental tool for studying the physics of magnetized plasmas. We aim to…

高能天体物理现象 · 物理学 2025-06-04 V. Bartolini , D. Dallacasa , J. L. Gómez , M. Giroletti , R. Lico , J. D. Livingston

We present the first 86 GHz VLBI observations of the radio galaxy 3C~120, together with contemporaneous 43 and 22 GHz polarimetric VLBA observations. The very high angular resolution obtained at 86 GHz provides an upper limit to the size of…

天体物理学 · 物理学 2009-10-31 Jose-Luis Gomez , Alan P. Marscher , Antonio Alberdi

Blazars are thought to possess a relativistic jet that is pointing toward the direction of the Earth and the elect of relativistic beaming enhances its apparent brightness. They radiate in all wavebands from the radio to the gamma-ray bands…

We present new, deep 8.5-GHz VLA observations of the nearby, low-luminosity radio galaxy 3C 296 at resolutions from 0.25 to 5.5 arcsec. These show the intensity and polarization structures of the twin radio jets in detail. We also derive…

天体物理学 · 物理学 2009-11-11 R. A. Laing , J. R. Canvin , A. H. Bridle , M. J. Hardcastle

One possible origin for polarization structures across jets of Active Galactic Nuclei (AGNs) with a central "spine" of orthogonal magnetic field and a "sheath" of longitudinal magnetic field along one or both edges of the jet is the…

星系天体物理 · 物理学 2015-06-23 Denise C. Gabuzda , Andrea Reichstein , Eamonn L. O'Neill

We present here uGMRT band 4 (~650MHz) polarization images of 8 BL~Lac objects belonging to the Palomar-Green (PG) `blazar' sample. A large fraction of the sources (~63%) reveal core-halo radio structures with most of the polarization…

星系天体物理 · 物理学 2023-10-16 Janhavi Baghel , P. Kharb , T. Hovatta , S. Gulati , E. Lindfors , Silpa S

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…

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,…

宇宙学与河外天体物理 · 物理学 2012-02-13 Shane P. O'Sullivan , Denise C. Gabuzda , Leonid I. Gurvits

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…

Polarization measurements provide strong constraints on magnetic fields in star-forming systems. While magnetic field estimates of a few kiloGauss (kG) have been obtained near the surface of low-mass protostars, there are no analogous…

We present an investigation of the compact structure of the AGN 2021+317 based on multi-epoch Very Long Baseline Interferometry (VLBI) observations at 15, 22, and 43 GHz in the period from 2013 through 2024. The VLBI images show a core-jet…

高能天体物理现象 · 物理学 2025-07-08 Haitian Shang , Wei Zhao , Xiaoyu Hong , Leonid I. Gurvits , Ailing Zeng , Tao An , Xiaopeng Cheng

The study of the polarization direction is crucial in the issue of restoring the spatial structure of the magnetic field in the active galaxy parsec-scale jets. But, due to relativistic effects, the magnetic field projected onto the…

高能天体物理现象 · 物理学 2022-12-28 Marina S. Butuzova

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…

高能天体物理现象 · 物理学 2015-06-12 J. C. Algaba

The Very Large Array has been used at five frequencies to study the structure and linear polarization of SS433 on scales as small as ~0.1" ~ 500 AU. Each jet consists of a sharp, curving ridge-line at the leading edge, plus significant…

天体物理学 · 物理学 2009-11-13 David H. Roberts , John F. C. Wardle , Scott L. Lipnick , Philip L. Selesnick , Simon Slutsky