Radio Continuum Emission from Galaxies: An Accounting of Energetic Processes

Radio continuum observations have proven to be a workhorse in our understanding of the star formation process (i.e., stellar birth and death) from galaxies both in the nearby universe and out to the highest redshifts. In this article we focus on how the ngVLA will transform our understanding of star formation by enabling one to map and decompose the radio continuum emission from large, heterogeneous samples of nearby galaxies on ≳ 10 pc scales to conduct a proper accounting of the energetic processes powering it. At the discussed sensitivity and angular resolution, the ngVLA will simultaneously be able to create maps of current star formation activity at ̃100 pc scales, as well as detect and characterize (e.g., size, spectral shape, density, etc.) discrete HII regions and supernova remnants on 10 pc scales in galaxies out to the distance of the Virgo cluster. Their properties can then be used to see how they relate to the local and global ISM and star formation conditions. Such investigations are essential for understanding the astrophysics of high-z measurements of galaxies, allowing for proper modeling of galaxy formation and evolution