Modelling of the free-free absorption in the starburst galaxy M82 and the Sgr A Complex

TL;DR

This paper models free-free absorption effects in the radio spectra of the starburst galaxy M82 and the Sgr A Complex, highlighting the importance of observational resolution and gas filling factors for accurate interpretation.

Contribution

It introduces a modeling approach that accounts for resolution and filling factors to better understand free-free absorption in galaxy radio spectra.

Findings

Resolution significantly affects absorption modeling accuracy.

Filling factor of ionized gas is crucial for correct spectral interpretation.

Modeling reproduces observed spectra of M82 and Sgr A Complex.

Abstract

The radio emission of normal galaxies may become opaque at low radio frequencies due to thermal ionized gas. We performed modelling of the free-free absorption to reproduce the ocal spectrum of SgrA Complex and the global spectrum of the starburst galaxy M82. We show the importance of resolution of radio observations and the value of filling factor of the absorbing gas for correct modelling of the absorption.