Contributed Talk - Splinter Stars

Wednesday, 15 September 2021, 09:00   (virtual Stars)

A Balancing Act: Observational determination of the pressures in HII regions across the Galactic Centre and nearby galaxies

Ashley Barnes
Universität Bonn, Argelander-Institut für Astronomie

High-mass stars inject a large amount of energy and momentum - stellar feedback - into the interstellar medium (ISM) during their relatively short lifetimes. The feedback from these stars can influence the ISM both locally (<1pc) and across their entire host galaxy (~1kpc), and occurs through a variety of feedback processes. Recent evidence suggests that feedback from young stars (i.e. pre-supernova) plays a crucial role in molecular cloud destruction, and stopping the formation of stars. The dominating processes by which this occur is, however, not clear; e.g. protostellar outflows, stellar winds, ionizing radiation. In this talk, I will discuss our recent efforts in a quantitative study of pre-SNe feedback mechanisms within both the centre Milky Way, and a large sample of nearby extragalactic systems. In these analyses, we focus on the balance of various internal and external pressures within young HII regions. The study of the Galactic Centre represents the first such study in a high-pressure environment, which has important implications for high-redshift environments. The study of extragalactic systems is the first to attempt such a study on a statistically significant sample of HII regions (~6000). Together with the available literature measurements, we can assess how dominant pressure term transitions over a huge dynamic range: around 5 dex in spatial dynamic range and 10 dex in pressure. I will end my talk by summarising the key advancements our this work in our understanding of young stellar feedback as a function of the environment.