Faraday Conversion in Turbulent Blazar Jets

TL;DR

This paper develops a radiative transfer scheme for the TEMZ model to simulate polarized emission in turbulent blazar jets, aiming to understand the origin of circular polarization.

Contribution

It introduces a new numerical method to produce synthetic polarized emission maps within the TEMZ model of turbulent jets.

Findings

Simulated polarization maps show expected linear and circular polarization patterns.

The model provides insights into how turbulence and magnetic fields influence polarization.

The scheme enables comparison of simulations with observational data.

Abstract

Low ($\lesssim 1\%$) levels of circular polarization (CP) detected at radio frequencies in the relativistic jets of some blazars can provide insight into the underlying nature of the jet plasma. CP can be produced through linear birefringence, in which initially linearly polarized emission produced in one region of the jet is altered by Faraday rotation as it propagates through other regions of the jet with varying magnetic field orientation. Marscher has begun a study of jets with such magnetic geometries using the Turbulent Extreme Multi-Zone (TEMZ) model, in which turbulent plasma crossing a standing shock in the jet is represented by a collection of thousands of individual plasma cells, each with distinct magnetic field orientations. Here we develop a radiative transfer scheme that allows the numerical TEMZ code to produce simulated images of the time-dependent linearly and circularly polarized intensity at different radio frequencies. In this initial study, we produce synthetic polarized emission maps that highlight the linear and circular polarization expected within the model.