Multi-Band Optical Variability of Blazar 1ES 2344+514 on Diverse Time-Scales

Abstract

This study presents the results of multi-band observations from 2022 to 2024 and Zwicky Transient Facility (ZTF) observations from 2018 to 2023, examining the flux variability of the blazar 1ES 2344+514 on diverse time-scales in the optical bands. The blazar has mild short-term variability (STV) and long-term variability (LTV), with small amplitudes of $\sim0.7$ mag and $0.4$ mag for the host subtracted- and included-light curves, respectively. The power-enhanced F-test and the nested Analysis of Variance (ANOVA) statistical tests of the six intra-day light curves show that the blazar has no minute-scale variability. The multiband color behavior analysis revealed a moderate redder-when-brighter (RWB) trend on intra-day time scales, while the LTV shows no detectable color behavior. We found a strong correlation between the ZTF optical light curves without any time lag, but no detectable correlations for the optical band emissions. From our periodicity searches using WWZ and LS methods, three significant quasi-periodic oscillation (QPO) signals in the ZTF light curves are found at about 1.02, 1.3, and 2.85 years. The observational results indicate that the blazar 1ES 2344+514 has a complex variability while emphasizing the need for future observations to unravel its underlying mechanisms.

Keywords

• Galaxies general
• galaxies active
• bl lacertae objects general
• bl lacertae objects individua 1ES 2344+514

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