Quasi-periodic behaviour in the radio and γ-ray light curves of blazar PKS 1510-089
: 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
: 2023
Monthly Notices of the Royal Astronomical Society
: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
: MON NOT R ASTRON SOC
: 519
: 4
: 4893
: 4901
: 9
: 0035-8711
: 1365-2966
DOI: https://doi.org/10.1093/mnras/stad008
: http://dx.doi.org/10.1093%2Fmnras%2Fstad008
: 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.