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.
@article{arxiv.1905.06621,
title = {Origin and Evolution of the Multi-band Variability in the Flat Spectrum Radio Source 4C 38.41},
author = {Juan Carlos Algaba and Sang Sung Lee and Bindu Rani and Dae-Won Kim and Motoki Kino and Jeffrey Hodgson and Guang-Yao Zhao and Do-Young Byun and Mark Gurwell and Sin-Cheol Kang and Jae-Young Kim and Jeong-Sook Kim and Soon-Wook Kim and Jongh-Ho Park and Sascha Trippe and Kiyoaki Wajima},
journal= {arXiv preprint arXiv:1905.06621},
year = {2019}
}
Comments
Proceedings for the 14th European VLBI Network Symposium & Users Meeting (EVN 2018) 8-11 October 2018, Granada, Spain