A1 Refereed original research article in a scientific journal
Quasi-periodic behaviour in the radio and γ-ray light curves of blazar PKS 1510-089
Authors: Li Xiao-Pan, Cai Yan, Yang Hai-Yan, Lähteenmäki Anne, Tornikoski Merja, Tammi Joni, Suutarinen Sofia, Yang Hai-Tao, Luo Yu-Hui, Wang Li-Sha
Publisher: OXFORD UNIV PRESS
Publication year: 2023
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Journal acronym: MON NOT R ASTRON SOC
Volume: 519
Issue: 4
First page : 4893
Last page: 4901
Number of pages: 9
ISSN: 0035-8711
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/stad008
Web address : http://dx.doi.org/10.1093%2Fmnras%2Fstad008
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/178954283
We explore the possible quasi-periodic oscillations (QPOs) of the blazar PKS 1510−089, utilizing the ∼38-yr Metsähovi flux density observations at 37 GHz and over 10-yr Fermi Large Area Telescope observations in the 0.1–300 GeV energy range. Both the flux distributions of the radio and γ-ray light curves suggest a lognormal distribution, and power spectral densities of both light curves can be well represented by a bending power-law model. Comparing the results from the weighted wavelet Z-transform and Lomb–Scargle periodogram approaches, a quasi-period of 1330 ± 55 d at a 99.80 per cent (>3σ) significance against the red noise background is observed in the radio light curve, whereas no similar modulation is seen in the γ-ray light curve. We briefly discuss the research actuality of blazar QPO phenomena and explain the observed radio QPO as the result of Keplerian motion in a supermassive binary black hole system and periodic modulation induced by the Lense–Thirring precession of the innermost portions of the accretion disc.
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