The SIGNALS from HII Regions

Abstract

In this invited review, I present an overview of HII regions and their central role in our understanding of galactic ecosystems. I begin with a brief introduction to the fundamental physics of ionized nebulae, outlining the processes that govern emission line formation and structure. From there, I explore what we can learn observationally from HII regions, including how their emission lines allow us to diagnose ionization conditions and excitation mechanisms via diagnostic tools like the BPT diagram. I discuss the distribution of HII regions across this parameter space and the physical drivers behind their location on such diagrams. The talk then focuses on chemical abundance measurements and how these measurements trace the evolutionary history and current state of teh host galaxy. I conclude by highlighting several promising directions for future work within the SIGNALS collaboration, leveraging the unprecedented size and resolution of the dataset to address outstanding questions in star formation, feedback, and chemical enrichment.

Ray Garner

TAMU Astronomy Postdoctoral Researcher

I’m a scientist, Star Wars fan, and amateur photographer raised in Georgia. My research interests include galaxy evolution, star formation, satellite galaxies, and nebular diagnostics.