Princeton University Star Formation/ISM Rendezvous (SFIR)

The density structure of the interstellar medium determines both where stars form and where they release the energy, momentum and heavy elements, that drive galaxy evolution. Although dense star-forming gas probably emerges from a variety of mechanisms, establishing the precise origin is observationally challenging because it requires quantifying gas motion over many orders of magnitude in spatial scale. In this talk, I will present our work in which we have measured the motion of molecular gas in the Milky Way and in nearby galaxy NGC 4321, thereby assembling observations that span an unprecedented spatial dynamic range. I will demonstrate how our analysis allows us to visualise the molecular interstellar medium in a new way, leading to the discovery of wave-like velocity fluctuations across all spatial scales and galactic environments. I will show how combining the analysis of density and velocity fluctuations can help to establish the physical mechanisms driving the motion of star-forming gas, and discuss how nested, interdependent gas flows control the formation ISM structure and its evolution towards star formation.