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

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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 ∼20 yr 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 P j / L bol , than both typical radio-detected AGNs and radio transients, consistent with their preference for low Eddington ratios. At the population level, the expected anticorrelation between radio emission and accretion rate is weak. However, a clear source-by-source anticorrelation emerges in a small subset of CL-AGNs with continuous multiepoch 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.
Funding Information
  • MOST ∣ National Key Research and Development Program of China (2023YFA1608100)

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