Modeling Star Formation Histories of Changing-look AGN Host Galaxies with Prospector Journal Article uri icon

Overview

abstract

  • Abstract; Changing-look active galactic nuclei (CL-AGNs), are AGNs that appear to transition between Seyfert Type 1 and 2 over periods of months to years. Several mechanisms to trigger these transitions have been proposed, but we have yet to conclusively determine their cause. Recent studies suggest CL-AGNs are hosted primarily in galaxies that are shutting down star formation (S. A. Dodd et al. 2021; W.-J. Liu et al. 2021; J. Wang et al. 2023), which may indicate a link between galaxy quenching and changing-look events. We use Prospector stellar population synthesis software (B. Johnson & J. Leja 2017; J. Leja et al. 2017; B. D. Johnson et al. 2021) to model nonparametric star formation histories for 39 CL-AGN host galaxies. We find that ; ; ; ; ; 4; ; ; 3; ; ; −; 12; ; ; +; 13; ; ; %; ; ; of our gold sample CL-AGNs at z < 0.15 are star-forming, while ; ; ; ; ; 2; ; ; 9; ; ; −; 10; ; ; +; 13; ; ; %; ; ; fall in the Green Valley of the stellar mass–specific star formation rate diagram. At z > 0.15, ; ; ; ; ; 5; ; ; 7; ; ; −; 18; ; ; +; 13; ; ; %; ; ; of CL-AGNs in the gold sample are star-forming and ; ; ; ; ; 2; ; ; 9; ; ; −; 14; ; ; +; 19; ; ; %; ; ; are in the Green Valley. CL-AGN hosts have similar star formation properties to the host galaxies of Seyfert 1 and 2 AGNs at z < 0.15 and to Seyfert 2 AGNs at z > 0.15. We find no statistically significant differences in the star formation properties of turn-on and turn-off CL-AGNs. We also find no evidence for rapid quenching in the Green Valley CL-AGNs. We conclude that CL-AGN state transitions are not associated with the formation history of CL-AGN host galaxies on large spatial scales, implying CL-AGN state transitions may instead result from nuclear-scale or accretion disk effects.

publication date

  • August 10, 2025

Date in CU Experts

  • August 14, 2025 8:20 AM

Full Author List

  • Verrico ME; French KD; Suess KA; Agrawal T; Lanz L; Luo Y; Patil P; Rowlands K; Shepherd M; Skarbinski M

author count

  • 10

Other Profiles

International Standard Serial Number (ISSN)

  • 0004-637X

Electronic International Standard Serial Number (EISSN)

  • 1538-4357

Additional Document Info

start page

  • 101

end page

  • 101

volume

  • 989

issue

  • 1