Ashley Bemis earned her PhD from McMaster University in 2020 working with Christine Wilson, was a Postdoctoral Fellow and ALMA Support Scientist in the Dutch ARC Node at Leiden Observatory until 2023, and is currently a Postdoctoral Fellow at the Waterloo Centre for Astrophysics. Her research interests include star formation in more extreme environments of nearby galaxies, with a focus on understanding the efficiency of star formation from dense, molecular gas.
Title: Testing Star Formation Models in Nearby Galaxies
Abstract: Resolved studies of nearby galaxies find that the efficiency of star formation from molecular gas can vary at sub-kpc scales. To first order, regions of higher star formation efficiency may have a higher abundance of dense, molecular gas that serves as the fuel for star formation. However, observations of dense gas at sub-kpc scales across nearby galaxies find that regions that are rich in dense gas do not always form stars more efficiently. One explanation for this is the suppression of star formation by the presence of higher ISM pressures in dense galactic environments, either in the form of high stellar potentials or enhanced levels of turbulence. In this talk I will present recent work comparing observations of dense, molecular gas and star formation with the predictions of turbulent models of star formation in a study of resolved, nearby galaxies using ALMA data. I will show that variations in the star formation efficiency of dense gas are a natural prediction of these models and match observed trends in our galaxy sample. Finally, I will introduce recent and ongoing work that shows the conversion between luminosities of traditional observational tracers of molecular gas mass (CO and HCN) can be impacted by a number of systematics that in turn affect observed star forming scaling relations.