Diverse Polarimetric Features of AGN Jets from Various Viewing Angles: Towards a Unified View

TL;DR

This study uses advanced simulations to explore how the polarization of emissions from AGN jets varies with viewing angle, revealing potential for combined polarimetry to infer black hole and jet properties.

Contribution

It introduces a comprehensive simulation framework demonstrating how polarization features depend on viewing angles, aiding unified interpretation of AGN emissions.

Findings

Polarization properties vary significantly with viewing angle.

Linear polarization is depolarized for edge-on observers.

Circular polarization signs depend on viewing angle.

Abstract

Here, we demonstrate that polarization properties show a wide diversity depending on viewing angles. To simulate images of a supermassive black hole and surrounding plasma, we performed a full-polarimetric general relativistic radiative transfer based on three-dimensional general relativistic magnetohydrodynamics models with moderate magnetic strengths. Under an assumption of a hot-jet and cold-disk in the electron temperature prescription, we confirmed a typical scenario where polarized synchrotron emissions from the funnel jet experience Faraday rotation and conversion in the equatorial disk. Further, we found that linear polarization vectors are inevitably depolarized for edge-on-like observers, whereas a portion of vectors survive and reach the observers in face-on-like cases. We also found that circular polarization components have persistent signs in the face-on cases, and changing signs in the edge-on cases. It is confirmed that these features are smoothly connected via intermediate viewing-angle cases. These results are due to Faraday rotation/conversion for different viewing angles, and suggest that a combination of linear and circular polarimetry can give a constraint on the inclination between the observer and black hole's (and/or disk's) rotating-axis and plasma properties in the jet--disk structure. These can also lead to a more statistical and unified interpretation for a diversity of emissions from active galactic nuclei.