Polarimetric studies of GRBs, AGN jets, and axion dark matter

TL;DR

This paper reviews recent polarimetric observations of relativistic jets in GRBs and AGNs, highlighting their role in understanding jet physics and proposing polarimetry as a tool to search for axion dark matter.

Contribution

It provides a comprehensive overview of polarimetric studies of GRB and AGN jets and introduces the novel idea of using polarimetry to detect axion dark matter.

Findings

First radio polarization detections of GRB afterglows

Insights into magnetic field structures in jets

Potential of polarimetry in dark matter searches

Abstract

Relativistic jets are collimated outflows with speeds close to light speed, which are associated with gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and so on. This article mainly overviews recent developments of polarimetric studies of GRBs and their afterglows in the gamma-ray and optical wavebands as well as the first detections of their radio polarization. Polarimetric observations and theoretical modelings can address the emission mechanism, magnetic field structure, and energetics of GRB jets and related collisionless plasma physics. Some of the discussed key physics are common with AGN jets. Furthermore, we mention that polarimetry of AGN jets and protoplanetary disks may be a novel approach to search for ultra-light axion dark matter.