High-Energy Polarization: Scientific Potential and Model Predictions

TL;DR

High-energy polarimetry in X-ray and gamma-ray bands offers a transformative approach to understanding astrophysical jets by probing their magnetic fields, radiation, and particle acceleration mechanisms with unprecedented detail.

Contribution

This paper reviews the scientific potential and model predictions for high-energy polarization measurements of jets, emphasizing their importance in constraining jet physics.

Findings

High-energy polarimetry can effectively probe jet magnetic fields and particle acceleration.

Model comparisons with observations will enhance understanding of jet composition and energy mechanisms.

High-energy polarimetry will significantly advance jet physics research.

Abstract

Understanding magnetic field strength and morphology is very important for studying astrophysical jets. Polarization signatures have been a standard way to probe the jet magnetic field. Radio and optical polarization monitoring programs have been very successful in studying the space- and time-dependent jet polarization behaviors. A new era is now arriving with high-energy polarimetry. X-ray and $\gamma$-ray polarimetry can probe the most active jet regions with the most efficient particle acceleration. This new opportunity will make a strong impact on our current understanding of jet systems. This paper summarizes the scientific potential and current model predictions for X-ray and $\gamma$-ray polarization of astrophysical jets. In particular, we discuss the advantages of using high-energy polarimetry to constrain several important problems in the jet physics, including the jet radiation mechanisms, particle acceleration mechanisms, and jet kinetic and magnetic energy composition. Here we take blazars as a study case, but the general approach can be similarly applied to other astrophysical jets. We conclude that by comparing combined magnetohydrodynamics (MHD), particle transport, and polarization-dependent radiation transfer simulations with multi-wavelength time-dependent radiation and polarization observations, we will obtain the strongest constraints and the best knowledge of jet physics.