A compact core-jet structure in the changing-look Seyfert NGC 2617
Journal article, 2021
The nearby face-on spiral galaxy NGC 2617 underwent an unambiguous 'inside-out' multiwavelength outburst in Spring 2013, and a dramatic Seyfert-type change probably between 2010 and 2012, with the emergence of broad optical emission lines. To search for the jet activity associated with this variable accretion activity, we carried out multiresolution and multiwavelength radio observations. Using the very long baseline interferometric (VLBI) observations with the European VLBI Network at 1.7 and 5.0 GHz, we find that NGC 2617 shows a partially synchrotron self-absorbed compact radio core with a significant core shift, and an optically thin steep-spectrum jet extending towards the north up to about 2 pc in projection. We also observed NGC 2617 with the electronic Multi-Element Remotely Linked Interferometer Network at 1.5 and 5.5 GHz, and revisited the archival data of the Very Large Array (VLA) and the Very Long Baseline Array (VLBA). The radio core had a stable flux density of similar to 1.4 mJy at 5.0 GHz between 2013 June and 2014 January, in agreement with the expectation of a supermassive black hole in the low accretion rate state. The northern jet component is unlikely to be associated with the 'inside-out' outburst of 2013. Moreover, we report that most optically selected changing-look active galactic nuclei (AGN) at z < 0.83 are sub-mJy radio sources in the existing VLA surveys at 1.4 GHz, and it is unlikely that they are more active than normal AGN at radio frequencies.
radio continuum: galaxies
galaxies: Seyfert
galaxies: individual: NGC 2617
galaxies: active
galaxies: jets
Author
Jun Yang
Chalmers, Space, Earth and Environment, Onsala Space Observatory
Joint Institute for VLBI in Europe (JIVE)
Zsolt Paragi
Joint Institute for VLBI in Europe (JIVE)
Robert J. Beswick
University of Manchester
Wen Chen
Chinese Academy of Sciences
Ilse M. van Bemmel
Joint Institute for VLBI in Europe (JIVE)
Qingwen Wu
Huazhong University of Science and Technology
Tao An
Chinese Academy of Sciences
Xiaocong Wu
Chinese Academy of Sciences
Lulu Fan
Shandong University
University of Science and Technology of China
J. B. R. Oonk
Leiden University
Netherlands Institute for Radio Astronomy (ASTRON)
Surfsara Bv
Xiang Liu
Chinese Academy of Sciences
Weihua Wang
Changzhou Institute of Technology
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 503 3 3886-3895Advanced Radio Astronomy in Europe (RADIONET3)
European Commission (EC) (EC/FP7/283393), 2012-01-01 -- 2015-12-31.
Subject Categories
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
Climate Research
DOI
10.1093/mnras/stab706