Observational constraints on stellar feedback in dwarf galaxies

Abstract

Feedback to the interstellar medium from ionizing radiation, stellar winds and supernovae is central to regulating star formation in galaxies. Owing to their low mass (<109 solar masses), dwarf galaxies are particularly susceptible to such processes, making them ideal sites for studying the detailed physics of feedback. In this Perspective, we summarize the latest observational evidence for feedback from star-forming regions and how this feedback drives the formation of ‘superbubbles’ and galaxy-wide winds. We discuss the important role of external ionizing radiation—reionization—for the smallest galaxies, and the observational evidence that this feedback directly impacts galaxy properties such as their star formation histories, metal contents, colours, sizes, morphologies and even their inner dark matter densities. We conclude with a look to the future, summarizing the key questions that remain to be answered and listing some of the outstanding challenges for galaxy formation theories.