0 Assigned ID: 4786 ----- Attempting Submission 1 (Wed May 24 23:03:39 GMT 2023) ----- To address one of the most important but poorly constrained aspects of stellar feedback in galaxies, we propose to use existing HST multiband photometry of 38 nearby star-forming galaxies to create a major new catalog of red supergiant (RSG) stars, which represent the likely progenitors of core collapse supernovae (SNe). We will compare the locations of RSGs to public, high quality ALMA and JWST maps to trace the local interstellar medium (ISM) structure, and make by far the most complete observational assessment of the ISM density into which SNe explode in galaxies. This is necessary because SN feedback plays a major role in galaxy formation, producing metals, driving outflows and turbulence, heating gas, and destroying clouds, but the precise impact of the explosions depend very sensitively on the ambient gas density into which the SNe explode, and observational constraints on these densities remain incredibly scarce because SNe are rare. By measuring the gaseous environments of thousands of future SNe across a large set of incredibly well-studied local galaxies, this proposal will yield by far the largest sample of ISM measurements at likely SN explosion sites ever assembled. All of the critical data for this project are public and observed, and the output will be the largest catalog of RSGs assembled for local galaxies, measurements of the ISM at the site of each RSG, and a major new assessment of how these SN ISM environments depends on host galaxy and location within the galaxy. The results will serve as key benchmarks for numerical studies of star formation, galaxies, and the ISM, and will have profound implications for our understanding of galaxy evolution. PI Sumit K. Sarbadhicary is an expert and led papers on supernova progenitors, supernova remnants and supernova feedback, particularly at the interface of observation and theory. He is currently leading work involving stars, supernovae and their co-existence in the interstellar medium from multi-wavelength data including HST, JWST, ALMA, and VLA. Co-PI David Thilker (JHU) is an expert in multiwavelength observational characterization of star formation in nearby galaxies and radio imaging of neutral hydrogen (HI) in circumgalactic environments. He specializes in ultraviolet imaging from HST, GALEX, UVIT, with emphasis on star formation occurring at low density. He is credited with the discovery of extended UV disks (XUV disks). Dr. Thilker has extensive experience with PSF fitting, and clump based, photometry. He is presently most active in the fields of stellar cluster and association populations, working at the forefront of the PHANGS-HST investigations on these topics. Co-I Leroy is an expert in star formation, stellar feedback, and multiwavelength observations of galaxies. He has specific expertise on multiwavelength observations of these targets, including the gas and dust data from ALMA, the VLA, MeerKAT, JWST, and more to which we intend to compare the HST massive star catalogs. Co-I Glover is an expert in the numerical modelling of stellar feedback in spiral galaxies. He will contribute to the interpretation of the results and the comparison with numerical simulations. Stellar Populations and the Interstellar Medium Stellar Physics and Stellar Types 0 Regular false false false false false false SUPPORTED