Optical Intraday Variability Studies of Ten Low Energy Peaked Blazars

TL;DR

This study monitored optical intraday variability in ten low energy peaked blazars, finding a 52% duty cycle of variability with most timescales exceeding observation durations, and discussing potential emission mechanisms.

Contribution

First systematic optical intraday variability study of ten low energy peaked blazars using structure function and correlation analysis.

Findings

Duty cycle of IDV in LBLs is approximately 52%.

Most variability timescales exceed observation durations.

Short observation periods may influence variability detection.

Abstract

We have carried out optical (R band) intraday variability (IDV) monitoring of a sample of ten bright low energy peaked blazars (LBLs). Forty photometric observations, of an average of ~ 4 hours each, were made between 2008 September and 2009 June using two telescopes in India. Measurements with good signal to noise ratios were typically obtained within 1-3 minutes, allowing the detection of weak, fast variations using N-star differential photometry. We employed both structure function and discrete correlation function analysis methods to estimate any dominant timescales of variability and found that in most of the cases any such timescales were longer than the duration of the observation. The calculated duty cycle of IDV in LBLs during our observing run is ~ 52%, which is low compared to many earlier studies; however, the relatively short periods for which each source was observed can probably explain this difference. We briefly discuss possible emission mechanisms for the observed variability.