Academia Sinica Logo

Star formation in galaxies is determined by the efficiency of the conversion of gas to stars and stellar feedback that shapes the reservoir of gas for future star formation. In this talk, I will introduce the PHANGS survey (Physics at High ANgular resolution in Nearby GalaxieS), a large multi-wavelength project to survey nearby galaxies at ~100-pc scale in molecular gas, star-forming regions, and stellar clusters, aiming to study the link between the small-scale physics of gas and star formation and galaxy properties and evolution.
I will also show you the preliminary results that probe the global property dependency of the relative distribution of molecular gas and star formation in nearby galaxies. We employ a simple approach to quantify the distributions of regions with different evolutionary stages of star formation: from quiescent molecular gas, to star-forming gas, and to regions of massive star formation only. At the best-match resolution of 150 pc, the distribution of regions with different evolutionary stages show a dependence on the stellar mass and morphology of galaxies, both globally and locally. Galactic dynamics (e.g., bar and spiral arms) also add to the complexity of the star formation process. Our results highlight the potential importance of galaxy properties for the gas-star formation cycle, and imply a global-property-dependent Kennicutt–Schmidt relation. However, any trends between galaxy properties and molecular gas and HII region distributions is visible only when the observed spatial scale is smaller than ~500 pc, indicating a critical resolution requirement to resolve the dependency.