Year: 2026
Type: article
Abstract: We report a rapid optical changing-look event in the Seyfert galaxy NGC 3227: the optical continuum faded by ∼70%, and broad H β emission nearly disappeared within weeks before recovering within 2 months. Damped random walk simulations calibrated to the source’s normal variability show that such a decline is unlikely for stochastic accretion fluctuations. The optical decline coincides with an X-ray spectral hardening event detected by Swift, indicating additional line-of-sight absorption. During the dim state, reverberation mapping yields a clear 6–8 day lag between the continuum and broad H β , placing the obscurer interior to the broad-line region. Photoionization calculations require a fully ionized Compton-thick column with N H ≈ 1.5 × 10 24 cm −2 to reproduce the optical continuum suppression. Together, these observations demonstrate that compact, high-column-density obscurers interior to the broad-line region can produce extreme optical changing-look behavior on timescales of weeks.
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,400
Funders: National Science Foundation, California Institute of Technology, Northwestern University, University of Washington, University of Warwick, Trinity College Dublin, National Natural Science Foundation of China, Stockholms Universitet, National Science and Technology Major Project, Deutsches Elektronen-Synchrotron, Institut National de Physique Nucléaire et de Physique des Particules
OpenAlex ID: W7223234352