JVLA Wideband Polarimetry Observations on a Sample of High Rotation Measure Sources

TL;DR

This study uses JVLA wideband polarimetry to analyze AGN with high Rotation Measures, revealing complex polarization behaviors and multiple polarized components, indicating intricate magnetic environments.

Contribution

It provides the first spectral resolution of multiple polarized components in high RM AGN using wideband JVLA observations, highlighting the complexity of their polarization structures.

Findings

Polarization angle and fractional polarization vary dramatically across the band.

RM is not constant within the wide band, indicating complex media.

Multiple polarized components are spectrally resolved in unresolved AGN.

Abstract

We present preliminary results of JVLA wideband full polarization observations of a sample of Active Galactic Nuclei (AGN) with very high Rotation Measure (RM) values, a sign of extreme environment. Polarization properties show a complex behaviour such that the polarization angle (PA) and fractional polarization (fp) change dramatically within the wide band. The measured RM is not constant within the wide band. Its complex behaviour reflects the complexity of the medium with the presence of several Faraday components. The depolarization has been studied by modelling the variations of the Stokes parameters Q and U together with the polarization parameters (PA and fp) with wavelength using combinations of the simplest existing depolarization models. With this JVLA study we could spectrally resolve multiple polarized components of unresolved AGN. These preliminary results reveal the complexity of these objects, but improvements to the depolarization modelling are needed to better understand the polarization structure of these sources.