Abstract

Galaxies provide a unique laboratory that involves nearly all branches of astrophysics. The challenge stands in unravelling a system where physical processes interact on scales spanning many orders of magnitude, ranging from the formation of stars to the large-scale cosmic web dominated by dark matter. The unknown physics of star formation and feedback represents the main uncertainty in our understanding of the formation of the first galaxies after the Big Bang and their evolution to today’s mature systems. By spatially resolving galaxies with the Hubble Space Telescope and the Very Large Telescope, I will show how galaxies build their bulges during their self-regulated growth 10 billion years ago, before they cease their star formation from the inside out. Using deep Keck spectroscopy, I further demonstrate that the pathways to quiescence are manifold, challenging current galaxy formation models. I will end by discussing upcoming observations with the James Webb Space Telescope, which – together with new numerical models that include radiation – will provide long-needed insights into the regulation of star formation in the early universe.