_version_ 1866929539605594112
author Meyer, Eileen T.
Laha, Sibasish
Shuvo, Onic I.
Roychowdhury, Agniva
Green, David A.
Rhodes, Lauren
Hankla, Amelia M.
Philippov, Alexander
Mbarek, Rostom
laor, Ari
Begelman, Mitchell C.
Sadaula, Dev R.
Ghosh, Ritesh
Bruni, Gabriele
Panessa, Francesca
Guainazzi, Matteo
Behar, Ehud
Masterson, Megan
Zhang, Haocheng
Yang, Xiaolong
Gurwell, Mark A.
Keating, Garrett K.
Williams-Baldwin, David
Bray, Justin D.
Bempong-Manful, Emmanuel K.
Wrigley, Nicholas
Bianchi, Stefano
Ricci, Federica
La Franca, Fabio
Kara, Erin
Georganopoulos, Markos
Oates, Samantha
Nicholl, Matt
Pal, Main
Cenko, S. Bradley
author_facet Meyer, Eileen T.
Laha, Sibasish
Shuvo, Onic I.
Roychowdhury, Agniva
Green, David A.
Rhodes, Lauren
Hankla, Amelia M.
Philippov, Alexander
Mbarek, Rostom
laor, Ari
Begelman, Mitchell C.
Sadaula, Dev R.
Ghosh, Ritesh
Bruni, Gabriele
Panessa, Francesca
Guainazzi, Matteo
Behar, Ehud
Masterson, Megan
Zhang, Haocheng
Yang, Xiaolong
Gurwell, Mark A.
Keating, Garrett K.
Williams-Baldwin, David
Bray, Justin D.
Bempong-Manful, Emmanuel K.
Wrigley, Nicholas
Bianchi, Stefano
Ricci, Federica
La Franca, Fabio
Kara, Erin
Georganopoulos, Markos
Oates, Samantha
Nicholl, Matt
Pal, Main
Cenko, S. Bradley
contents We present multi-frequency (5-345 GHz) and multi-resolution radio observations of 1ES 1927+654, widely considered one of the most unusual and extreme changing-look active galactic nuclei (CL-AGN). The source was first designated a CL-AGN after an optical outburst in late 2017 and has since displayed considerable changes in X-ray emission, including the destruction and rebuilding of the X-ray corona in 2019-2020. Radio observations prior to 2023 show a faint and compact radio source typical of radio-quiet AGN. Starting in February 2023, 1ES 1927+654 began exhibiting a radio flare with a steep exponential rise, reaching a peak 60 times previous flux levels, and has maintained this higher level of radio emission for over a year to date. The 5-23 GHz spectrum is broadly similar to gigahertz-peaked radio sources, which are understood to be young radio jets less than ~1000 years old. Recent high-resolution VLBA observations at 23.5 GHz now show resolved extensions on either side of the core, with a separation of ~0.15 pc, consistent with a new and mildly relativistic bipolar outflow. A steady increase in the soft X-ray band (0.3-2 keV) concurrent with the radio may be consistent with jet-driven shocked gas, though further observations are needed to test alternate scenarios. This source joins a growing number of CL-AGN and tidal disruption events which show late-time radio activity, years after the initial outburst.
format Preprint
id arxiv_https___arxiv_org_abs_2406_18061
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Late-time radio brightening and emergence of a radio jet in the changing-look AGN 1ES 1927+654
Meyer, Eileen T.
Laha, Sibasish
Shuvo, Onic I.
Roychowdhury, Agniva
Green, David A.
Rhodes, Lauren
Hankla, Amelia M.
Philippov, Alexander
Mbarek, Rostom
laor, Ari
Begelman, Mitchell C.
Sadaula, Dev R.
Ghosh, Ritesh
Bruni, Gabriele
Panessa, Francesca
Guainazzi, Matteo
Behar, Ehud
Masterson, Megan
Zhang, Haocheng
Yang, Xiaolong
Gurwell, Mark A.
Keating, Garrett K.
Williams-Baldwin, David
Bray, Justin D.
Bempong-Manful, Emmanuel K.
Wrigley, Nicholas
Bianchi, Stefano
Ricci, Federica
La Franca, Fabio
Kara, Erin
Georganopoulos, Markos
Oates, Samantha
Nicholl, Matt
Pal, Main
Cenko, S. Bradley
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
We present multi-frequency (5-345 GHz) and multi-resolution radio observations of 1ES 1927+654, widely considered one of the most unusual and extreme changing-look active galactic nuclei (CL-AGN). The source was first designated a CL-AGN after an optical outburst in late 2017 and has since displayed considerable changes in X-ray emission, including the destruction and rebuilding of the X-ray corona in 2019-2020. Radio observations prior to 2023 show a faint and compact radio source typical of radio-quiet AGN. Starting in February 2023, 1ES 1927+654 began exhibiting a radio flare with a steep exponential rise, reaching a peak 60 times previous flux levels, and has maintained this higher level of radio emission for over a year to date. The 5-23 GHz spectrum is broadly similar to gigahertz-peaked radio sources, which are understood to be young radio jets less than ~1000 years old. Recent high-resolution VLBA observations at 23.5 GHz now show resolved extensions on either side of the core, with a separation of ~0.15 pc, consistent with a new and mildly relativistic bipolar outflow. A steady increase in the soft X-ray band (0.3-2 keV) concurrent with the radio may be consistent with jet-driven shocked gas, though further observations are needed to test alternate scenarios. This source joins a growing number of CL-AGN and tidal disruption events which show late-time radio activity, years after the initial outburst.
title Late-time radio brightening and emergence of a radio jet in the changing-look AGN 1ES 1927+654
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2406.18061