Optical Quasiperiodic Oscillations with 550 Day Periodicity in the Reverberation-mapped Broad Line Quasar PG 1411+442

In this paper, optical quasiperiodic oscillations (QPOs) with 550 day periodicity related to a candidate subparsec binary black hole (BBH) system are reported in the reverberation-mapped broad line quasar PG 1411+442 but with a different line profile of broad H α from that of broad H β in its rms sp...

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Main Author: Xue-Guang Zhang
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/ada284
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author Xue-Guang Zhang
author_facet Xue-Guang Zhang
author_sort Xue-Guang Zhang
collection DOAJ
description In this paper, optical quasiperiodic oscillations (QPOs) with 550 day periodicity related to a candidate subparsec binary black hole (BBH) system are reported in the reverberation-mapped broad line quasar PG 1411+442 but with a different line profile of broad H α from that of broad H β in its rms spectrum. First, considering the sine function to describe the 18.8 yr long light curves from the Catalina Sky Survey, All-Sky Automated Survey for Supernovae, and Zwicky Transient Facility, 550 day periodicity can be confirmed with a confidence level higher than 5 σ . Second, the stable 550 day optical QPOs can be reconfirmed with confidence levels higher than 5 σ by the generalized Lomb–Scargle periodogram, the sine-like phase-folded light curves, and the weighted wavelet z -transform technique determined power maps. Third, based on simulated light curves by the continuous autoregressive process, a confidence level higher than 3.5 σ can be confirmed for the optical QPOs not related to intrinsic active galactic nucleus (AGN) variability. Moreover, considering the spatial separation of central two black hole (BH) accreting systems with smaller than expected sizes of broad emission line regions, a central total BH mass higher than 10 ^6 M _⊙ could lead to few effects of supposed BBH systems on estimated virial BH masses. Meanwhile, disk precession is not preferred due to the similar estimated sizes of the optical and near-ultraviolet emission regions, and jet precession can be ruled out due to PG 1411+442 being a radio-quiet quasar. The results strongly indicate it would be practicable, by applying very different line profiles of broad Balmer emission lines, to detect candidate BBH systems in normal broad line AGN in the near future.
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spelling doaj-art-9be9b9825d904aa184b1477dbbfc4ac72025-08-20T03:17:34ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01979214710.3847/1538-4357/ada284Optical Quasiperiodic Oscillations with 550 Day Periodicity in the Reverberation-mapped Broad Line Quasar PG 1411+442Xue-Guang Zhang0https://orcid.org/0000-0001-5458-8354Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, GuangXi University , Nanning 530004, People’s Republic of China ; xgzhang@gxu.edu.cnIn this paper, optical quasiperiodic oscillations (QPOs) with 550 day periodicity related to a candidate subparsec binary black hole (BBH) system are reported in the reverberation-mapped broad line quasar PG 1411+442 but with a different line profile of broad H α from that of broad H β in its rms spectrum. First, considering the sine function to describe the 18.8 yr long light curves from the Catalina Sky Survey, All-Sky Automated Survey for Supernovae, and Zwicky Transient Facility, 550 day periodicity can be confirmed with a confidence level higher than 5 σ . Second, the stable 550 day optical QPOs can be reconfirmed with confidence levels higher than 5 σ by the generalized Lomb–Scargle periodogram, the sine-like phase-folded light curves, and the weighted wavelet z -transform technique determined power maps. Third, based on simulated light curves by the continuous autoregressive process, a confidence level higher than 3.5 σ can be confirmed for the optical QPOs not related to intrinsic active galactic nucleus (AGN) variability. Moreover, considering the spatial separation of central two black hole (BH) accreting systems with smaller than expected sizes of broad emission line regions, a central total BH mass higher than 10 ^6 M _⊙ could lead to few effects of supposed BBH systems on estimated virial BH masses. Meanwhile, disk precession is not preferred due to the similar estimated sizes of the optical and near-ultraviolet emission regions, and jet precession can be ruled out due to PG 1411+442 being a radio-quiet quasar. The results strongly indicate it would be practicable, by applying very different line profiles of broad Balmer emission lines, to detect candidate BBH systems in normal broad line AGN in the near future.https://doi.org/10.3847/1538-4357/ada284Active galactic nucleiQuasarsSupermassive black holesLomb-Scargle periodogram
spellingShingle Xue-Guang Zhang
Optical Quasiperiodic Oscillations with 550 Day Periodicity in the Reverberation-mapped Broad Line Quasar PG 1411+442
The Astrophysical Journal
Active galactic nuclei
Quasars
Supermassive black holes
Lomb-Scargle periodogram
title Optical Quasiperiodic Oscillations with 550 Day Periodicity in the Reverberation-mapped Broad Line Quasar PG 1411+442
title_full Optical Quasiperiodic Oscillations with 550 Day Periodicity in the Reverberation-mapped Broad Line Quasar PG 1411+442
title_fullStr Optical Quasiperiodic Oscillations with 550 Day Periodicity in the Reverberation-mapped Broad Line Quasar PG 1411+442
title_full_unstemmed Optical Quasiperiodic Oscillations with 550 Day Periodicity in the Reverberation-mapped Broad Line Quasar PG 1411+442
title_short Optical Quasiperiodic Oscillations with 550 Day Periodicity in the Reverberation-mapped Broad Line Quasar PG 1411+442
title_sort optical quasiperiodic oscillations with 550 day periodicity in the reverberation mapped broad line quasar pg 1411 442
topic Active galactic nuclei
Quasars
Supermassive black holes
Lomb-Scargle periodogram
url https://doi.org/10.3847/1538-4357/ada284
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