X-ray Polarization at the Crossroads

TL;DR

This paper discusses how the Imaging X-ray Polarimetry Explorer can address key questions about magnetars, including their surface states, vacuum birefringence, and hard X-ray emission, through simulations and model analysis.

Contribution

It presents the potential of the new X-ray polarimetry instrument to resolve longstanding questions about magnetar physics.

Findings

Simulations show the instrument can detect polarization signatures of magnetar emissions.

Predicted polarization measurements can distinguish between different surface and emission models.

The study highlights the importance of X-ray polarization in understanding extreme magnetic environments.

Abstract

We argue that measurements of X-ray polarization using the recently launched Imaging X-ray Polarimetry Explorer will answer many open questions about magnetars in particular the physical state of their surfaces, whether vacuum birefringence exists, and the nature of the hard X-ray emission from these objects. We outline the capabilities of the instrument, specific models and the results of simulations for the magnetar 4U~0142+61.