« Unravelling the formation of globular clusters in low-metallicity environments »
James Webb Space Telescope has now started to uncover the first proto-globular clusters (GCs) that emerged during the Cosmic Dawn. These clusters were compact (effective radii ~parsecs) and exhibited extreme stellar densities, ideal to harbour energetic massive stars and possibly intermediate mass black holes. The detailed conditions and time-scales of star formation and stellar feedback in the proto-GCs of the low-mass and low-metallicity galaxies at high-redshifts are however still unclear. This is both due to the limiting resolution (parsecs) and sensitivity in even the most optimal gravitationally lensed detections; and the lack of complementary high-fidelity simulations able to capture the key astrophysical processes of clustered star formation on small, sub-parsec scales.
In the GRIFFIN project (Galaxy Realizations Including Feedback From INdividual massive stars) we examine the formation and evolution of resolved star clusters up to the GC-mass range using high-resolution (sub-parsec, star-by-star) hydrodynamical simulations. Our low-metallicity dwarf galaxy simulations account for the radiation, stellar winds and supernovae of individual stars. We have shown that massive star clusters form hierarchically and rapidly over time-scales of less than 10 Myr. During formation, they can be self-enriched in light-element-rich stellar winds of very massive stars, while supernova ejecta escape in metal-enriched outflows. Recently, we supplemented the methodology with a regularised integrator to accurately solve the stellar gravitational dynamics on small spatial scales. This was shown to be critically important for the modelling of more realistic star cluster life cycles from formation until disruption in the tidal field of the host galaxy. In this talk, I will discuss some of the key results of GRIFFIN and future avenues toward unravelling the cosmic origin of GCs.