Rutgers University Astrophysics Colloquium

It has long been recognized that the properties of resolved stellar populations in nearby galaxies can provide key insights into a variety of astrophysics, including understanding structure formation, the impact of cosmic reionization on galaxies, and constraints on the expansion of the universe. The study of resolved stars was transformed by the high sensitivity and spatial resolution of the Hubble Space Telescope (HST), and is now being transformed again with the more powerful James Webb Space Telescope (JWST). New HST and JWST results have far-reaching implications and range from providing the most detailed and quantitative measures of the growth of low-mass structures across cosmic timescales, to determining precise distances to galaxies which are essential inputs for measuring the local value of the Hubble Constant. In this talk, I will highlight recent results from resolved star studies on very low-mass galaxies with HST data (including data on ultra-faint dwarf galaxies discovered by our team at Rutgers), present the first star formation history of a galaxy with JWST data, and introduce new distance calibrations derived from HST and JWST data on nearby galaxies, the latter of which paves the way for a JWST-based measure of the Hubble Constant. I will also highlight additional insights we are gaining on the evolution of galaxies from these data.