colloquium Anita Zanella: The contribution of high-redshift star-forming regions to galaxy evolution

Observations have shown that local galaxies have modest star formation rates and form the bulk of their stars in giant molecular clouds. In comparison, galaxies in the early Universe have high star formation rates and host large star-forming regions (dubbed “clumps”), 10 – 1000 times larger, brighter, and more massive than local giant molecular clouds. Interestingly, the formation phase of clumps has rarely been observed and their fate is highly uncertain. Are they born in-situ due to fragmentation of gas-rich disks or are they small satellite galaxies that merged with the host? Do they migrate inward and contribute to the formation of the galaxy bulge or are they rapidly disrupted by stellar feedback? Do they play a role in the mass assembly and structural evolution of the host galaxy? I will discuss our latest results derived from spatially-resolved HST, VLT/MUSE and ALMA datasets, as well as mock observations created from hydrodynamical simulations, which provide some answers to these open questions.