Revealing the spectral properties of magnetic turbulence by synchrotron polarization gradients

TL;DR

This paper introduces a new gradient-based method to measure the spectral properties of magnetic turbulence using synchrotron polarization data, validated with synthetic data and applied to Galactic observations, revealing a specific power-law spectrum.

Contribution

The paper presents a novel gradient technique for analyzing magnetic turbulence spectra from polarization data, applicable even under strong Faraday depolarization conditions.

Findings

Confirmed the feasibility of the gradient technique with synthetic data.

Applied the method to ATCA Galactic data, finding a $E\propto k^{-10/3}$ spectral law.

Demonstrated the method's potential for low-frequency polarization observations.

Abstract

Based on the modern understanding of MHD turbulence theory, we propose a new method for measuring the spectral properties of magnetic turbulence by synchrotron polarization gradient analysis. Using synthetic polarization observational data, we first confirm the feasibility of the gradient technique to determine the scaling properties of magnetic turbulence. We then apply this technique to the Galactic plane survey data from the Australia Telescope Compact Array (ATCA) and obtain the power-law spectral feature of the Galactic magnetic turbulence of $E\propto k^{-10/3}$. Gradient techniques open up a new way to obtain spectral properties of magnetic turbulence from polarization observations, such as the Low-Frequency Array for Radio Astronomy (LOFAR), in the presence of low-frequency and strong Faraday depolarization.