Jordan Turner (U. Wyoming): "Constraining Star Formation Timescales Using Spatial Correlation of Star Clusters and GMCs"


In the hierarchical view of star formation, giant molecular gas clouds (GMCs) undergo fragmentation to form small-scale structures made up of stars and star clusters which constitute the larger structures within galaxies. In this talk, we will discuss the connection between young star clusters and cold gas across a range of galactic environments by combining the PHANGS-ALMA catalog of GMCs with the star cluster catalogs from PHANGS-HST. We first show how the star cluster properties (age, mass, reddening) are determined from spectral energy distribution (SED) fitting using the PHANGS-HST UV-optical photometry. The star clusters are then spatially matched with the GMCs and, using the cluster ages provided by the SED fitting, we statistically derive the timescales of star formation within GMCs. We apply this technique across a sample of 11 nearby star-forming galaxies with a range of galactic environments (i.e., centers, bars, spiral arms, etc.) thus providing insight into the connection between star formation at small-scales and large-scale galactic structure. Additionally, we measure the autocorrelation of the star clusters and GMCs as well as the cross-correlation to quantify the fractal nature of hierarchical star formation.