English

Radio Activity Across Accretion State Changes in Changing-look AGNs: Insights from FIRST and VLASS over Two Decades

Astrophysics of Galaxies 2026-07-05 v1

Abstract

Changing-look active galactic nuclei (CL-AGNs) provide a unique opportunity to probe the coupling between accretion flows and relativistic jets in supermassive black holes. We investigate the long-term radio behavior of CL-AGNs over approximately 20 years by combining FIRST and VLASS observations with quasi-simultaneous optical spectroscopy and photometry. From a parent sample of 1092 CL-AGNs, we identify 58 sources with radio detections. Radio-detected CL-AGNs exhibit systematically higher radio kinetic efficiency, quantified by Pj/LbolP_{\rm j}/L_{\rm bol}, than both typical radio-detected AGNs and radio transients, consistent with their preference for low Eddington ratios. At the population level, the expected anti-correlation between radio emission and accretion rate is weak. However, a clear source-by-source anti-correlation emerges in a small subset of CL-AGNs with continuous multi-epoch coverage. We further identify four radio transients, including both radio turn-on and turn-off events, and one source exhibiting a multiwavelength flare that may be indicative of tidal disruption event-like activity. These results suggest that radio activity in CL-AGNs is not governed by instantaneous accretion state changes but is instead regulated by long-term accretion history and jet evolution, with additional stochastic or transient channels contributing in rare cases.

Keywords

Cite

@article{arxiv.2607.04328,
  title  = {Radio Activity Across Accretion State Changes in Changing-look AGNs: Insights from FIRST and VLASS over Two Decades},
  author = {Zhi-Qiang Chen and Wei-Jian Guo and Victoria A. Fawcett and Jun-Jie Jin and Wen-Ke Ren and Heng-Xiao Guo and Min-Feng Gu and Yan-Mei Chen and Lu Feng and Hu Zou and Qi-Rong Yuan},
  journal= {arXiv preprint arXiv:2607.04328},
  year   = {2026}
}

Comments

Accepted for publication in ApJ