NGC 3227 Blinks: An Extreme Changing-look Event in a Seyfert Galaxy
6 affiliations
- 1University of Wyoming
- 2Chinese Academy of Sciences
- 3University of Chinese Academy of Sciences
- 4SUPA School of Physics and Astronomy
- 5Space Telescope Science Institute
- 6University of Nevada
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.
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BibTeX
@article{zhang20263227,
title = {{NGC 3227 Blinks: An Extreme Changing-look Event in a Seyfert Galaxy}},
author = {Kaiwen Zhang and Michael S. Brotherton and Pu Du and Dong-Wei Bao and Bi-Xuan Zhao and Feng-na Fang and Yan-Rong Li and Chen Hu and Ming Xiao and Keith Horne and Gerard A. Kriss and Daniel Proga and Jian-Min Wang},
journal = {The Astrophysical Journal Letters},
year = {2026},
month = nov,
doi = {10.3847/2041-8213/aeb6c3},
url = {https://iopscience.iop.org/article/10.3847/2041-8213/aeb6c3},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - NGC 3227 Blinks: An Extreme Changing-look Event in a Seyfert Galaxy
AU - Kaiwen Zhang
AU - Michael S. Brotherton
AU - Pu Du
AU - Dong-Wei Bao
AU - Bi-Xuan Zhao
AU - Feng-na Fang
AU - Yan-Rong Li
AU - Chen Hu
AU - Ming Xiao
AU - Keith Horne
AU - Gerard A. Kriss
AU - Daniel Proga
AU - Jian-Min Wang
PY - 2026
DA - 2026/11/06
JO - The Astrophysical Journal Letters
DO - 10.3847/2041-8213/aeb6c3
UR - https://iopscience.iop.org/article/10.3847/2041-8213/aeb6c3
AB - 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.
SN - 2041-8213
SN - 2041-8205
ER -