Investigating Optical Variability of the Blazar S5 0716+714 On Diverse Time-scales

Abstract

We present the results of the observational study of the blazar S5 0716+716 in the optical bands B, V, R, and I between March 2019 and August 2023 to investigate its variability on diverse time-scales. The blazar was followed up by the T60 robotic telescope in Turkey for 416 nights to obtain long-term variability during this period. In order to search for intraday variability of the object, we have carried out 21 nights of observations with the T100 telescope for at least 1 hour. The blazar showed a ~2.47 mag variation in the optical R-band during our monitoring period, the brightest state on 18.01.2020 (MJD 58866) as R=12.109$\pm$0.011 and the faintest state on 23.03.2019 (MJD 58565) as R=14.580$\pm$0.013. We employed the nested ANOVA test and the power enhanced F-test to quantify intraday variability which showed that the blazar was significantly variable in the R-band on 12 out of 21 nights. Correlation analysis of the light curves shows that the emission in the BVRI optical bands was strongly correlated both in the short and long term without any time lag. The blazar has likely quasi-periods of 186$\pm$30, 532$\pm$76 days in the optical R-band light curve according to the WWZ, and the LS periodogram. The IDV and LTV features are discussed within the frame of prospective scenarios.