Optical intraday variability analysis for the BL Lacertae object 1ES 1426+42.8

ABSTRACT The observation data of blazar 1ES 1426+42. 8 were obtained using the 1. 02 m optical telescope of Yunnan Observatories during 2021 to 2023. Intraday variability (IDV) is detected on seven nights. We use the turbulent model to investigate the mechanism of IDV in 1ES 1426+42. 8. The fitting light curves match the actual IDV curves well. Using this model, we obtain the parameters such as the size of turbulent cells and the width of pulses in the jet. A possible short-lived quasi-periodic oscillation (QPO) of 58. 55 8. 09 min was detected on 2022 April 26 whose light curve exhibits eight cycles at 3 global significance and confirmed by several different techniques. Through a more detailed analysis of the light curve of this night, we find that the period is shortened from 54. 23 min (4) to 29. 71 min (3). The possible QPO and period shortening phenomenon are best explained by the processes of magnetic reconnections.