The flaring activity of blazar AO 0235+164 during year 2021

Abstract

Context. The blazar AO 0235+164, located at redshift $z=0.94$, has displayed interesting and repeating flaring activity in the past, the latest episodes occurring in 2008 and 2015. In 2020, the source brightened again, starting a new flaring episode that peaked in 2021. Aims. We study the origin and properties of the 2021 flare in relation to previous studies and the historical behavior of the source, in particular to the 2008 and 2015 flaring episodes. Methods. We analyze the multi-wavelength photo-polarimetric evolution of the source. From Very Long Baseline Array images, we derive the kinematic parameters of new components associated with the 2021 flare. We use this information to constrain a model for the spectral energy distribution of the emission during the flaring period. We propose an analytical geometric model to test whether the observed wobbling of the jet is consistent with precession. Results. We report the appearance of two new components that are ejected in a different direction than previously, confirming the wobbling of the jet. We find that the direction of ejection is consistent with that of a precessing jet.The derived period independently agrees with the values commonly found in the literature. Modeling of the spectral energy distribution further confirm that the differences between flares can be attributed to geometrical effects.

Accepted 15 May 2024

References in corpus (10)

• Kinematics of Parsec-Scale Jets of Gamma-Ray Bright Blazars at 43 GHz during Ten Years of the VLBA-BU-BLAZAR Program
• Probing Acceleration and Turbulence at Relativistic Shocks in Blazar Jets
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. III. Characterisation of total flux density and polarisation variability of relativistic jets
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. I. The program, calibration, and calibrators data products
• Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state
• POLAMI: Polarimetric Monitoring of Active Galactic Nuclei at Millimetre Wavelengths. II. Widespread circular polarisation
• Multiwavelength periodicity search in a sample of $\gamma$-ray bright blazars
• On the distribution of fluxes of gamma-ray blazars: hints for a stochastic process?
• The RoboPol Program: Optical Polarimetric Monitoring of Blazars
• The Repeating Flaring Activity of Blazar AO 0235+164

Cited by in corpus (2)

• PKS 2155-304: Long-Term Optical Photometric Monitoring and Variability Analysis
• Parsec-scale jet precession and a putative supermassive binary black hole system in the blazar AO 0235+164