pith. sign in

arxiv: 2510.18445 · v2 · pith:3BQASU54new · submitted 2025-10-21 · 🌌 astro-ph.GA

Discovery of Repeating Transitions in 16 Changing-look Active Galactic Nuclei

Qian Dong , Zhi-Xiang Zhang , Wei-Min Gu , Mouyuan Sun , Wei-Jian Guo , Zhen-Yi Cai , Jun-Xian Wang , Yong-Gang Zheng This is my paper
classification 🌌 astro-ph.GA
keywords agnsspectroscopicactivechanging-lookcurvesgalacticidentifylight
0
0 comments X
read the original abstract

The repeating changing-look active galactic nuclei (RCL AGNs) exhibit multiple appearances and disappearances of broad emission lines (BELs), whose underlying mechanism remains a puzzle. Expanding the sample of RCL AGNs is valuable for constraining the transition timescale and probing the accretion physics driving CL behaviors. This study aims to identify RCL AGNs using the multi-epoch spectroscopic data of confirmed CL AGNs from the Sloan Digital Sky Survey, Large Sky Area Multi-Object Fiber Spectroscopic Telescope, and Dark Energy Spectroscopic Instrument, supplemented with mid-infrared (MIR) light curves. Through selection criteria and visual inspection, we identify 22 RCL AGNs among 299 CL AGNs, corresponding to an occurrence rate of about 7\%, indicating that repeated transitions are not extremely rare in CL AGNs. Among the 22 RCL AGNs, 16 are newly identified, which significantly expands the known RCL AGN sample. Based on the spectra and densely sampled MIR light curves, we derive MIR variability timescales for 18 RCL AGNs, and find no significant correlation between the timescale and the black hole mass.

This paper has not been read by Pith yet.

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Forward citations

Cited by 4 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

  1. SDSSJ110546.07+145202.4: The first long-duration radio changing-look NLS1 galaxy

    astro-ph.HE 2026-04 unverdicted novelty 7.0

    SDSSJ110546.07+145202.4 is the first known long-duration radio changing-look NLS1 galaxy whose outburst is explained by an accretion-rate change that triggered a powerful radio jet.

  2. Identifying Changing-Look AGN Transitions in Light Curve Data with the Zwicky Transient Facility

    astro-ph.GA 2026-04 unverdicted novelty 6.0

    A criterion of |Δg| > 0.4 mag and |Δ(g-r)| > 0.2 mag detects photometric CL-AGN transitions in 9.6% of known hosts with 1.6% false positive rate from simulations.

  3. Changing-look Active Galactic Nuclei from SDSS, LAMOST and DESI Survey

    astro-ph.GA 2026-05 unverdicted novelty 4.0

    Multi-epoch spectroscopic cross-matching yields 45 CLAGNs (43 turn-off, 2 turn-on) including 12 repeating sources that trace a high-low-high accretion-state path in the black-hole mass versus Eddington-ratio plane.

  4. Accretion-Mode Transition: The Driver Behind Spectral Changes in Changing-Look AGNs

    astro-ph.HE 2026-04 unverdicted novelty 4.0

    Changing-look AGNs exhibit spectral changes because their accretion disks transition to a truncated state at low Eddington ratios around 2%, reducing ionizing photons and weakening broad emission lines.