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Dynamical Balance and Vertical Distribution of the Molecular ISM in Nearby Galaxies

Jiayi Sun (McMaster) — November 23, 2021

Abstract

The dynamical state of molecular gas on large and small scales is intimately related to its ability to form stars. A common hypothesis states that the kinetic energy in molecular gas should on average match the combination of self-gravity, external gravity, and ambient pressure, which puts the bulk gas in a dynamical equilibrium. I will present my recent work that tested this decades-old hypothesis with high-quality data from the PHANGS survey, and then put our results into the framework of self-regulated star formation in galaxies. I will also demonstrate the implications of these results on the vertical distribution of gas in galaxy disks, and present a novel approach to determine the molecular disk scale height. This approach is being calibrated and tested in numerical simulations and will be widely applied to the PHANGS galaxy sample.