Revealing the Spectral Properties of Galactic Interstellar Medium by Survey Observations

TL;DR

This study uses polarization frequency analysis on multi-frequency radio survey data to uncover differences in turbulence properties of the Galactic interstellar medium between the disk and halo, revealing a steeper slope in the disk.

Contribution

It introduces a novel polarization frequency analysis method and compares it with traditional techniques to study ISM turbulence properties across different Galactic regions.

Findings

ISM in the Galactic disk has a steeper spectral slope than Kolmogorov.

ISM in the Galactic halo exhibits a Kolmogorov-like slope.

The turbulence cascade process differs between the Galactic disk and halo.

Abstract

Based on multi-frequency radio polarization survey datasets, we investigate the spectral characteristics of the Galactic interstellar medium (ISM) using the polarization frequency analysis (PFA) method, referred to as polarization variance. By comparing this novel PFA technique with the traditional power spectrum approach, and by cross-examining data from two distinct surveys, we aim to reinforce the robustness of our findings. Our analysis reveals that the ISM scaling slope in the Galactic disk is steeper than the classic Kolmogorov slope, whereas the ISM scaling slope in the Galactic halo aligns with the Kolmogorov slope. We suggest a distinct turbulence cascade process operating in the Galactic halo compared to the Galactic disk.