The Cloud-Scale Structure of Molecular Gas in Nearby Galaxies

Séminaire IPAG de Annie Hugues (IRAP), jeudi 22 septembre 2016 à 11h00, salle Manuel Forestini IPAG

Cloud-scale models of star formation predict that the transformation of gas into stars depends on the local density, turbulent velocity dispersion, and gravitational boundedness of the interstellar gas. With new facilities (ALMA/NOEMA), the latest generation of nearby galaxy surveys will systematically access these conditions in other galaxies at the scale of individual star-forming clouds. This is a major opportunity for linking the cloud-scale physics of star formation to galactic-scale processes, and reconciling the Galactic and extragalactic views of star formation. In this contribution, I will highlight new results from our comparative analysis of the cloud-scale molecular gas properties — surface density, velocity dispersion, gravitational boundedness, mass distribution — and star formation activity across a small yet diverse sample of nearby galaxies. Both within and among galaxies, we observe variations in molecular gas properties that support a context-dependent (i.e. non-universal) relationship between gas density and star formation, and the role of galactic environment in regulating the small-scale density distribution of the ISM.