Detection of quasi‐periodic oscillations in γ‐ray and optical light curves of the BL Lac 4FGL J0650.7 + 2503

Abstract

In this work, we have assembled the long-term variability data of the blazar 4FGL J0650.7 + 2503 in the γ-ray and the optical bands, spanning about 11.9 and 8.6 years, respectively. The light curves are then analyzed by using Lomb-Scargle Periodogram, Weighted Wavelet Z-transform, Jurkevich and discrete correlation function techniques, and the results reveal two possible timescales of quasi-periodic oscillation: 500 ± 37 days for γ-ray and 330 ± 20 days for optical.To explore the origin of the γ-ray, we investigated between the optical and γ-ray band correlations, and found that the correlation between the two bands is very significant. This correlation can be reasonably explained by the lepton self-synchro-Compton model. Based on the supermassive binary black hole system model, we estimate the primary black hole mass M ∼ 8.5 × 10 8 M ⊙ .