Origin and Evolution of the Multi-band Variability in the Flat Spectrum Radio Source 4C 38.41

Juan Carlos Algaba; Sang Sung Lee; Bindu Rani; Dae-Won Kim; Motoki Kino; Jeffrey Hodgson; Guang-Yao Zhao; Do-Young Byun; Mark Gurwell; Sin-Cheol Kang; Jae-Young Kim; Jeong-Sook Kim; Soon-Wook Kim; Jongh-Ho Park; Sascha Trippe; Kiyoaki Wajima

arXiv · 1905.06621

Origin and Evolution of the Multi-band Variability in the Flat Spectrum Radio Source 4C 38.41

Juan Carlos Algaba·Sang Sung Lee·Bindu Rani·Dae-Won Kim·Motoki Kino·Jeffrey Hodgson·Guang-Yao Zhao·Do-Young Byun·Mark Gurwell·Sin-Cheol Kang·Jae-Young Kim·Jeong-Sook Kim·Soon-Wook Kim·Jongh-Ho Park·Sascha Trippe·Kiyoaki Wajima

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Abstract

The flat spectrum radio quasar 4C 38.41 showed a significant increase of its radio flux density during the period 2012 March - 2015 August which correlates with gamma-ray flaring activity. Multi-frequency simultaneous VLBI observations were conducted as part of the interferometric monitoring of gamma-ray bright active galactic nuclei (iMOGABA) program and supplemented with additional monitoring observations at various bands across the electromagnetic spectrum. The epochs of the maxima for the two largest gamma-ray flares coincide with the ejection of two respective new VLBI components and the evolution of the physical properties seem to be in agreement with the shock-in-jet model. Derived synchrotron self absorption magnetic fields, of the order of 0.1 mG, do not seem to dramatically change during the flares, and are much smaller, by a factor 10,000, than the estimated equipartition magnetic fields, indicating that the source of the flare may be associated with a particle dominated emitting region.

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Juan Carlos Algaba, Sang Sung Lee, Bindu Rani, Dae-Won Kim, Motoki Kino, Jeffrey Hodgson, Guang-Yao Zhao, Do-Young Byun, Mark Gurwell, Sin-Cheol Kang, Jae-Young Kim, Jeong-Sook Kim, Soon-Wook Kim, Jongh-Ho Park, Sascha Trippe, Kiyoaki Wajima. 2019-05-16. Origin and Evolution of the Multi-band Variability in the Flat Spectrum Radio Source 4C 38.41. https://arxiv.org/abs/1905.06621

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