The most massive of these galaxies are up to ten times larger than the present-day Milky Way, but have reached this mass in a fraction of the time. How can they build up so much mass in so little time, and what makes them suddenly stop forming stars? These questions are at the heart of the project that Francesco Valentino will carry out at the Cosmic Dawn Center over three years, starting from 2024.

"One way to form and »quench« galaxies, as we say, could be linked to two galaxies crashing into each other," explains Valentino. "But we know that these violent events of merging galaxies did not happen sufficiently often to explain all the quenched galaxies that we see. Rather than looking at the merging galaxies, we intend to study more normal, massive galaxies and their evolution in the early Universe."

The galaxies will be studied not only with James Webb, but also with the ground-based telescope VLT and in Chile. With the Sapere Aude grant, Francesco Valentino will additionally be able to hire two postdocs and one PhD student, to participate in his research group.