Detection of quasi-periodic oscillations in the long-term radio light curves of the blazar OT 081

ABSTRACT We report the detection of quasi-periodic oscillations (QPOs) in radio light curves at 4.8, 8, and 14.5 GHz blazar OT 081, by means Weighted Wavelet Z-transform (WWZ) Lomb–Scargle periodogram (LSP) methods. The LSP diagrams time-averaged WWZ powers demonstrate several significant claims QPOs above 4? confidence level: ?850 ?1500 d 4.8-GHz curve, ?850, ?1120, ?1540 8-GHz ?1130 14.5-GHz curve. Keplerian orbit parameters a binary black hole system have been estimated, assuming QPO appearing all three wavebands is real periodicity. Moreover, pure geometrical scenario with blobs moving helically inside jet provides another plausible explanation for detected QPOs.