Unveiling The Physics of Star Formation and Feedback in Galaxies

TL;DR

This paper explores how radio observations reveal the role of feedback processes, like cosmic rays and magnetic fields, in regulating star formation and shaping the interstellar medium in galaxies.

Contribution

It provides new observational evidence linking massive star formation to the energy balance in the ISM through cosmic rays and magnetic fields, using multi-frequency radio surveys.

Findings

Massive star formation influences the energy balance in the ISM.

Radio surveys trace thermal and nonthermal components of the ISM.

Magnetic fields and cosmic rays are significantly affected by star formation.

Abstract

Recent studies show the importance of feedback in the evolution of the star formation rate in the Universe. However, the nature and physics of the feedback are still pressing questions. Radio continuum observations can provide unique dust-unbiased tracers of massive star formation and of the interstellar medium (ISM) and hence are ideal to address the regulation of star formation in galaxies. Our multi-frequency and multi-resolution radio surveys in nearby galaxies enable us to trace various phases of star formation and dissect the thermal and nonthermal ISM in galaxies. Mapping the cosmic ray electron energy index and magnetic field strength, we have found observational evidence that massive star formation significantly affects the energy balance in the ISM through the injection and acceleration of cosmic rays and the amplification of magnetic fields. How the next generation of stars could form in such a magnetized and turbulent ISM will be addressed in our 'EVLA cloud-scale survey of the local group galaxy M33' and in forthcoming surveys with the SKA.