Modelling the polarization dichotomy of Active Galactic Nuclei

TL;DR

This paper models the polarization signatures of Active Galactic Nuclei using Monte Carlo simulations, successfully reproducing the observed polarization dichotomy through complex scattering regions.

Contribution

It introduces a comprehensive polarization model of AGN that includes multiple scattering regions and explores their effects on polarization signatures.

Findings

Model reproduces the observed polarization dichotomy.

Polarization depends on optical depth, dust composition, and geometry.

Complex scattering regions are crucial for accurate polarization modeling.

Abstract

I present polarization modelling of Active Galactic Nuclei in the optical/UV range. The modelling is conducted using the Monte-Carlo radiative transfer code Stokes, which self-consistently models the polarization signature of a complex model arrangement for an active nucleus. In this work I include three different scattering regions around the central source: an equatorial electron scattering disk, an equatorial obscuring dusty torus, and polar electron scattering cones. I investigate the resulting dependencies of the V-band polarization for different optical depths of the scattering cones, different dust compositions inside the torus, and various half-opening angles of the torus/polar cones. The observed polarization dichotomy can be successfully reproduced by the model.