Multi-band optical variability on diverse timescales of blazar 1E 1458.8+2249

Abstract

This study presents an analysis of the optical variability of the blazar 1E 1458.8+2249 on diverse timescales using multi-band observations, including observations in the optical BVRI bands carried out with the T60 and T100 telescopes from 2020 to 2023 and ZTF gri data from 2018 to 2023. On seven nights, we searched for intraday variability using the power-enhanced F-test and the nested ANOVA test, but no significant variability was found. The long-term light curve shows a variability behaviour in the optical BVRI bands with amplitudes of $\sim 100\%$ and in the gri bands with amplitudes of $\sim 120\%$, including short-term variability of up to $\sim 1.1$ mag. Correlation analysis revealed a strong correlation between the optical multi-band emissions without any time lag.From 62 nightly SEDs, we obtained spectral indices between 0.826 and 1.360, with an average of $1.128\pm 0.063$. The relationships of both spectral indices and colour with respect to brightness indicate a mild BWB trend throughout the observation period, both intraday and long-term. We also performed a periodicity search using the Weighted Wavelet Z-transform (WWZ) and Lomb-Scargle methods. A recurrent optical emission pattern with a quasi-periodicity of $\sim 340$ days is detected in the combined V- and R-band light curves. The observational results indicate that the blazar 1E 1458.8+2249 has a complex variability, while emphasising the need for future observations to unravel its underlying mechanisms.

10 pages, 9 figures, 4 tables; published in PASA

References in corpus (18)

• Periodic Oscillations in the Intra-day Optical Light Curves of the Blazar S5 0716+714
• Optical Intra-day Variability in Blazars
• A model for periodic blazars
• Detection of Possible Quasi-periodic Oscillations in the Long-term Optical Light Curve of the BL Lac Object OJ 287
• Kinematics of and emission from helically orbiting blobs in a relativistic magnetized jet
• Revisiting Quasi-Periodic modulation in $\gamma$-ray Blazar PKS 2155-304 with Fermi Pass 8 data
• Multi-band optical variability studies of BL Lacertae
• On the reliability of microvariability tests in quasars
• VLBI observations of seven BL Lac objects from RGB sample
• Transient Quasi-Periodic Oscillations at $\gamma$-rays in the TeV Blazar PKS 1510-089
• A Consolidated Framework of the Color Variability in Blazars: Long-Term Optical/Near-Infrared Observations of 3C 279
• Optical Flux and Spectral Variability of the TeV blazar PG 1553+113
• Multi-band behaviour of the TeV blazar PG 1553+113 in optical range on diverse timescales
• Detection of Quasi-Periodic Oscillations in the Blazar S4 0954+658 with TESS
• Optical Quasi-periodic Oscillations in the TESS light curves of three blazars
• A 3.8yr optical quasi-periodic oscillations in blue quasar SDSS J132144+033055 through combined light curves from CSS and ZTF
• Characterizing the optical nature of the blazar S5 1803+784 during its 2020 flare
• Multicolour Optical Variability Monitoring of Blazars with High Time Resolution