Galaxies under the (gravitational) lens: how star clusters shape star formation across cosmic times
Matteo Messa (INAF - OAS)
Tuesday 15/04/2025 @ 14:00, Sala Antonio Sollima (IV piano Battiferro)
Star formation is a hierarchical process that, at the smallest scales, leads to the formation of star clusters. These clusters host many of newly formed massive stars and are key drivers of the feedback mechanisms that regulate the star formation cycle. The large-scale galactic environment influences these small scales, with denser galaxies capable of forming more massive clusters, hosting the majority of the recent star-formation activity. While these trends are well-established in the local Universe, galaxies at higher redshift are known to behave differently. During Cosmic Noon (z ~ 1–3), galaxies were more gas-rich and turbulent, with star formation rates up to ten times higher than those observed locally. Approaching the epoch of reionization and beyond (z > 6), galaxies become more compact and less massive, often exhibiting intense nebular emission. Recently, thanks to the synergy between gravitational lensing and the exceptional sensitivity and resolution of JWST, we are beginning to resolve individual star clusters and compact star-forming regions out to redshifts of ~10. Do these distant structures follow the same correlations observed locally, or do we need new physical ingredients to explain how galaxies form and evolve across cosmic time?