Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. II. Statistical Properties from the First Data Release

Abstract We present the identification of changing-look active galactic nuclei (CL-AGNs) from the Dark Energy Spectroscopic Instrument First Data Release and Sloan Digital Sky Survey Data Release 16 at z ≤ 0.9. To confirm the CL-AGNs, we utilize spectral flux calibration assessment via an [O iii ]-based calibration, pseudophotometry examination, and visual inspection. This rigorous selection process allows us to compile a statistical catalog of 561 CL-AGNs, encompassing 527 H β , 149 H α , and 129 Mg ii CL behaviors. In this sample, we find (1) a 283:278 ratio of turn-on to turn-off CL-AGNs. (2) The median Eddington ratio for CL-AGNs in the dim state is approximately λ Edd ∼ 0.01. (3) A strong correlation between the change in the luminosity of the broad emission lines (BELs) and variation in the continuum luminosity, with Mg ii and H β displaying similar responses during CL phases. (4) The Baldwin–Phillips–Terlevich diagram for CL-AGNs shows no statistical difference from the general AGN catalog. (5) Five CL-AGNs are associated with asymmetrical mid-infrared flares, possibly linked to tidal disruption events. Given the large CL-AGN sample and the stochastic sampling of spectra, we propose that some CL phenomena are inherently due to typical AGN variability during low accretion rates, particularly for CL phenomenon only occurring on one BEL. Finally, we introduce a monotonically dimming CL phase for objects characterized by a gradual decline over decades in the light curve and the complete disappearance of entire BELs in faint spectra, indicative of a real transition in the accretion disk.

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Publication Details

Journal
The Astrophysical Journal Supplement Series
Published
2025-05-01
DOI
https://doi.org/10.3847/1538-4365/adc124
Citations
13
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
15.01

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article

Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. II. Statistical Properties from the First Data Release

Zhiwei Pan, D. Brooks, Michael S. Schubnell, Graziano Rossi et al.
13 citations
The Astrophysical Journal Supplement Series
Galaxies: Formation, Evolution, Phenomena
15.01
article

Changing-look Active Galactic Nuclei from the Dark Energy Spectroscopic Instrument. II. Statistical Properties from the First Data Release

Zhiwei Pan, D. Brooks, Michael S. Schubnell, Graziano Rossi, Jipeng Sui, Gregory Tarlé, Kyle Dawson, Andreu Font-Ribera, Benjamin Alan Weaver, Laurent Le Guillou, David Sprayberry, Axel de la Macorra, Martin Landriau, Victoria A. Fawcett, Siwei Zou, Marc Manera, J. Aguilar, Eusebio Sanchez, Satya Gontcho A Gontcho, ENRIQUE GAZTAÑAGA, M. Siudek, Claire Greenwell, Steven P. Ahlen, Aaron Meisner, Theodore S. Kisner, D. M. Alexander, R. Kehoe, John Moustakas, Wei-Jian Guo, Yun-Ao Xiao, Hu Zou, T. Claybaugh, P. Doel, Ramon Miquel, Gaston Gutierrez, Francisco Prada
article en
13 citations

Abstract

Abstract We present the identification of changing-look active galactic nuclei (CL-AGNs) from the Dark Energy Spectroscopic Instrument First Data Release and Sloan Digital Sky Survey Data Release 16 at z ≤ 0.9. To confirm the CL-AGNs, we utilize spectral flux calibration assessment via an [O iii ]-based calibration, pseudophotometry examination, and visual inspection. This rigorous selection process allows us to compile a statistical catalog of 561 CL-AGNs, encompassing 527 H β , 149 H α , and 129 Mg ii CL behaviors. In this sample, we find (1) a 283:278 ratio of turn-on to turn-off CL-AGNs. (2) The median Eddington ratio for CL-AGNs in the dim state is approximately λ Edd ∼ 0.01. (3) A strong correlation between the change in the luminosity of the broad emission lines (BELs) and variation in the continuum luminosity, with Mg ii and H β displaying similar responses during CL phases. (4) The Baldwin–Phillips–Terlevich diagram for CL-AGNs shows no statistical difference from the general AGN catalog. (5) Five CL-AGNs are associated with asymmetrical mid-infrared flares, possibly linked to tidal disruption events. Given the large CL-AGN sample and the stochastic sampling of spectra, we propose that some CL phenomena are inherently due to typical AGN variability during low accretion rates, particularly for CL phenomenon only occurring on one BEL. Finally, we introduce a monotonically dimming CL phase for objects characterized by a gradual decline over decades in the light curve and the complete disappearance of entire BELs in faint spectra, indicative of a real transition in the accretion disk.

The Astrophysical Journal Supplement SeriesVol. 278(1)
Laboratoire de Physique Nucléaire et de Hautes Énergies (FR)
National Science Foundation, U.S. Department of Energy, Gordon and Betty Moore Foundation, Ministerio de Ciencia, Innovación y Universidades, European Commission, National Natural Science Foundation of China, Chinese Academy of Sciences, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Narodowa Agencja Wymiany Akademickiej, Office of Science, Science and Technology Facilities Council, Agencia Estatal de Investigación, Division of Astronomical Sciences
Openalex Percentile: Top 1%
Galaxies: Formation, Evolution, Phenomena
15.01
DOIOpen Access PDFOpenAlex
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