Quasi-simultaneous two band optical variability of the blazars 1ES 1959+650 and 1ES 2344+514

TL;DR

This study monitored two high-energy peaked blazars in optical bands to investigate microvariability and short-term variability, finding no intra-night variability but detecting short-term variability in one source, contributing to understanding blazar variability patterns.

Contribution

First simultaneous optical monitoring of these two blazars in B and R bands, revealing differences in short-term variability behavior.

Findings

No intra-night variability detected in either blazar.

Short-term variability observed in 1ES 1959+650 but not in 1ES 2344+514.

High-energy peaked BL Lacs are less variable intra-night compared to low-energy peaked BL Lacs.

Abstract

We report the results of quasi-simultaneous two filter optical monitoring of two high-energy peaked blazars, 1ES 1959+650 and 1ES 2344+514, to search for microvariability and short-term variability (STV). We carried out optical photometric monitoring of these sources in an alternating sequence of B and R pass-bands, and have 24 and 19 nights of new data for these two sources, respectively. No genuine microvariability (intra-night variability) was detected in either of these sources. This non-detection of intra-night variations is in agreement with the conclusions of previous studies that high-energy peaked BL Lacs are intrinsically less variable than low-energy peaked BL Lacs in the optical bands. We also report the results of STV studies for these two sources between July 2009 and August 2010. Genuine STV is found for the source 1ES 1959+650 but not for 1ES 2344+514. We briefly discuss possible reasons for the difference between the intra-night variability behaviour of high- and low-energy peaked blazars.