Jet Kinematics of the Quasar 4C +21.35 from Observations with the KaVA Very Long Baseline Interferometry Array
Abstract
We present the jet kinematics of the flat spectrum radio quasar (FSRQ) 4C +21.35 using time-resolved KaVA very long baseline interferometry array radio maps obtained from September 2014 to July 2016. During two out of three observing campaigns, observations were performed bi-weekly at 22 and 43 GHz quasi-simultaneously. At 22 GHz, we identified three jet components near the core with apparent speeds up to (14.4+/-2.1)c. The timing of the ejection of a new component detected in 2016 is consistent with a gamma-ray flare in November 2014. At 43 GHz, we found four inner jet (<3 mas) components with speeds from (3.5+/-1.4)c to (6.8+/-1.5)c. Jet component speeds tend to be higher with increasing distances from the core. We compared our data with archival Very Long Baseline Array (VLBA) data from the Boston University (BU) 43 GHz and the Monitoring Of Jets in Active galactic nuclei with VLBA Experiments (MOJAVE) 15.4 GHz monitoring programs. Whereas MOJAVE data and our data are in good agreement, jet speeds obtained from the BU Program data in the same time period are about twice as high as the ones we obtain from the KaVA data. The discrepancy at 43 GHz indicates that radio arrays with different angular resolution identify and trace different jet features even when the data are obtained at the same frequency and at the same time. The flux densities of jet components decay exponentially, in agreement with a synchrotron cooling time scale of about 1 year. Using known electron Lorentz factor values (about 9,000), we estimate the magnetic field strength to be around 1-3 micro-Tesla. When adopting a jet viewing angle of 5 degrees, the intrinsic jet speed is of order 0.99c.
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Cite
@article{arxiv.1904.02894,
title = {Jet Kinematics of the Quasar 4C +21.35 from Observations with the KaVA Very Long Baseline Interferometry Array},
author = {Taeseok Lee and Sascha Trippe and Motoki Kino and Bong Won Sohn and Jongho Park and Junghwan Oh and Kazuhiro Hada and Kotaro Niinuma and Hyunwook Ro and Taehyun Jung and Guang-Yao Zhao and Sang-Sung Lee and Juan-Carlos Algaba and Kazunori Akiyama and Kiyoaki Wajima and Satoko Sawada-Satoh and Fumie Tazaki and Ilje Cho and Jeffrey Hodgson and Jeong Ae Lee and Yoshiaki Hagiwara and Mareki Honma and Shoko Koyama and Tao An and Yuzhu Cui and Hyemin Yoo and Noriyuki Kawaguchi and Duk-Gyoo Roh and Se-Jin Oh and Jae-Hwan Yeom and Dong-Kyu Jung and Chungsik Oh and Hyo-Ryoung Kim and Ju-Yeon Hwang and Do-Young Byun and Se-Hyung Cho and Hyun-Goo Kim and Hideyuki Kobayashi and Katsunori M. Shibata and Zhiqiang Shen and Wu Jiang and Jee Won Lee},
journal= {arXiv preprint arXiv:1904.02894},
year = {2019}
}
Comments
11 pages, 9 figures, 3 tables. To appear in MNRAS (submitted 2018 June 7; accepted 2019 March 28)