Uncovering star formation feedback and magnetism in galaxies with radio continuum surveys

TL;DR

This paper uses radio continuum surveys to explore how star formation feedback influences galaxy evolution, magnetic fields, and cosmic rays, revealing that star formation energizes cosmic rays and amplifies magnetic turbulence in galaxies.

Contribution

It demonstrates the effectiveness of multi-frequency polarization radio surveys in dissecting star formation feedback effects on the interstellar medium in galaxies.

Findings

Cosmic rays are injected and propagate from star-forming regions.

Star formation feedback energizes cosmic ray electrons.

Magnetic fields are amplified by star formation, affecting galaxy structure.

Abstract

Recent studies show the importance of the star formation feedback in changing the energetic and structure of galaxies. Dissecting the physics of the feedback is hence crucial to understand the evolution of galaxies. Full polarization radio continuum surveys can be ideally performed to trace not only star formation but also the energetic components of the interstellar medium (ISM), the magnetic fields and cosmic ray electrons. Using the SKA precursors, we investigate the effect of the massive star formation on the ISM energy balance in nearby galaxies. Our multi-scale and multi-frequency surveys show that cosmic rays are injected in star forming regions and lose energy propagating away from their birth place. Due to the star formation feedback, cosmic ray electron population becomes younger and more energetic. Star formation also amplifies the turbulent magnetic field inserting a high pressure which is important in energy balance in the ISM and structure formation in the host galaxy.