# The Optical Polarization Variability of PKS 2155-304: Correlations at Low and High Energies

## TL;DR

This study analyzes over five years of optical polarization data of blazar PKS 2155-304, correlating polarization angle rotations with multi-wavelength flares to understand jet behavior and emission mechanisms.

## Contribution

It provides the first extensive multi-wavelength polarization analysis of PKS 2155-304, linking polarization angle rotations to flaring activity across different energies.

## Key findings

- Large polarization angle rotations (>80°) are associated with optical and gamma-ray flares.
- Polarization angles tend to align with the radio jet during rotations.
- Flares often coincide with significant polarization variability.

## Abstract

Gamma-ray emitting blazars have been the targets of many recent or ongoing monitoring programmes. The resulting multi-wavelength data archives are ideal for studying the quiescent and variable behaviour of the blazar PKS 2155-304. Here, observations of the optical polarization of the source between 2009 and 2014 (> 5 years) are presented, together with overlapping radio, photometric and gamma-ray measurements. During this time the source displayed significant variability at all wavelengths, with several prominent flares seen for the optical and gamma-ray intensity. These flares are typically associated with large rotations (>80{\deg}) in the polarization angle, during which the polarization angle appears to be oriented parallel to the position angle of the spatially resolved radio jet. Our aim is to determine if these large polarization angle rotations are correlated to the multi-wavelength outbursts seen in PKS 2155-304 in order to examine how changes in the polarization angle (and its orientation relative to the jet) relate to changes in the spectral energy distribution of the source.