Gamma-rays in the radio galaxy 3C 84: A complex situation

Jeffrey A. Hodgson, Bindu Rani, Junghwan Oh

Research output: Contribution to journalConference articlepeer-review

Abstract

3C 84 is a nearby Active Galactic Nucleus (AGN) that is unique in that is believed that we are observing near the true jet launching region - unlike blazars. The source is active in g-rays and has been detected with Fermi since its launch in 2008, including being detected at TeV energies with other instruments. Due to the relative proximity of the source (z=0.018), it provides a unique opportunity to pinpoint the location of the g-ray emission by combining the g-ray data with very long baseline inteferometry (VLBI) data. A study using the Korean VLBI network (KVN) showed that the g-rays occur in both downstream jet emission and the region near where the jet is launched. Further analysis of the kinematics using Wavelet Image Segmentation and Evaluation (WISE) algorithm, which uses 2-dimensional cross-correlations to statistically derive the kinematics of high-resolution 7 mm VLBA data show that the g-ray emission is caused by a fast-travelling shock catching a slower moving shock and then interacting with the external medium, in behaviour reminiscent of a long duration gamma-ray burst (GRB). This could explain why such high energy flaring is seen in such low Doppler boosted sources. Finally, we show some early results from a study of the jet launching region using the Global mm- VLBI Array (GMVA). The nucleus appears to have a consistent double nuclear structure that is likely too broad to be the true jet base.

Original languageEnglish
JournalProceedings of Science
Volume2017-October
StatePublished - 2017
Event7th International Fermi Symposium, IFS 2017 - Garmisch-Partenkirchen, Germany
Duration: 15 Oct 201720 Oct 2017

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