2020PASP..132d4101Y

We have assembled the historical light curves of the BL Lac Object 3FGL J0449.4-4350 at optical and γ-ray bands, the time spanning about 10 yr, analyzed the periodic variability of the light curves by using four different methods (Lomb-Scargle periodogram, REDFIT38, Jurkevich and DACF). We detected a marginally possible quasi-periodic oscillation of ∼450 days. Assuming it originates from the helical motion jet in a supermassive binary black hole system undergoing major merger, we estimate the primary black hole mass M ∼ 7.7 x 10⁹ M_☉. To explore the origin of the γ-ray, we investigated the optical-γ-ray correlations using discrete correlation function method, and found that the correlation between the two bands is very significant. This strong correlation tends to imply lepton self-synchro-Compton model to produce the γ-ray.