A Galaxy Doesn’t Forget: Why You Should Trust Your Resolved SFHs from Photometric Observations

Connection information: https://science.nasa.gov/astrophysics/programs/cosmic-origins/community/galaxies-sig-seminar-6-oct-2026/

Speaker: Charlotte Olsen | CUNY City Tech

Abstract:

Spatially resolved galaxy properties are routinely derived from integral-field spectroscopy and increasingly from multi-band photometry as a wealth of photometric data becomes available in large surveys. Spatially resolved star formation histories (SFHs) offer a detailed view of galaxy growth and quenching by tracing the timing and location of star formation within a galaxy. However, stellar migration between spaxels can strongly bias these reconstructions. Quantifying how much bias we expect in observations remains challenging because many zoom-in simulations do not resolve initial stellar dispersions or migration rates. We use the well-validated h277 Milky-Way-mass cosmological zoom simulation, which resolves both via advanced molecular-cloud modeling, to compare the actual radial distribution of star formation to the distribution inferred from the resolved SFHs up to a lookback time of ~1.6 Gyr in several evolutionary windows. Measuring migration rates in annuli matched to typical spaxel scales, we quantify how well we can recover the radial profiles from resolved SFHs at different time steps and find them consistent in slope and the relative shape of the scatter up to 1 Gyr lookback time.

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https://science.nasa.gov/astrophysics/programs/cosmic-origins/science-groups