2015/10/28 by Jae-Young Kim, JAE-YOUNG KIM, SASCHA TRIPPE +13
Physics and Astronomy · #Active galactic nucleus #Astrophysical Phenomena and Observations #Astrophysical jet #Astrophysics and Cosmic Phenomena #BL Lac object #Circular polarization #Galaxies: Formation, Evolution, Phenomena #Line-of-sight #Linear polarization #Polarimetry #Polarization (electrochemistry) #Very-long-baseline interferometry #astro-ph.GA #astro-ph.HE
paper · pdf · doi:10.5303/jkas.2015.48.5.285
14 pages, 17 figures, 4 tables. To appear in JKAS (received 2015 July 27; accepted 2015 October 25). Note the PAGaN II companion paper by J. Oh et al
arxiv created 2015/10/28 · openalex publication_date 2015/10/31 · arxiv updated 2015/11/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Active Galactic Nuclei (AGN) with bright radio jets offer the opportunity to study the structure of and physical conditions in relativistic outflows. For such studies, multi-frequency polarimetric very long baseline interferometric (VLBI) observations are important as they directly probe particle densities, magnetic field geometries, and several other parameters. We present results from first-epoch data obtained by the Korean VLBI Network (KVN) within the frame of the Plasma Physics of Active Galactic Nuclei (PAGaN) project. We observed seven radio-bright nearby AGN at frequencies of 22, 43, 86, and 129 GHz in dual polarization mode. Our observations constrain apparent brightness temperatures of jet components and radio cores in our sample to >108.01 K and >109.86 K, respectively. Degrees of linear polarization mL are relatively low overall: less than 10%. This indicates suppression of polarization by strong turbulence in the jets. We found an exceptionally high degree of polarization in a jet component of BL Lac at 43 GHz, with mL ∼ 40%. Assuming a transverse shock front propagating downstream along the jet, the shock front being almost parallel to the line of sight can explain the high degree of polarization.