Detection of quasi-periodic oscillations from the blazar PKS 1510-089

We report the detection of quasi-periodic oscillations (QPOs) in the radio light curve of the blazar PKS 1510-089 spanning nearly 38 years, by means of the weighted wavelet Z-transform and Lomb–Scargle periodogram methods. Prominent QPOs with high confidence (>4 σ ) of 570± 30 , 800± 30, and 1070± 40 days in the 8 GHz light curve, 430± 10 and 1080± 30 days in the 14.5 GHz light curve have been identified after estimating the significance against the red noise background. Moreover, the most significant QPO of about 1080 days exceeded 4 σ confidence level at two of the three frequencies but did not exactly persist the whole observations, indicating that QPOs in blazars are transient in nature. We suggest that the search for QPO in blazar light curves should evaluate the statistical significances and consider the influences of the colored noise, after reviewing earlier QPO claims of PKS 1510-089.