Understanding the quenching of star formation in the distant Universe

Around 10 billion years ago the most massive galaxies underwent a dramatic transformation, switching off their star formation and also changing from disc-like galaxies to compact spheroidal systems. We still do not understand why this transformation occurs, or the key physical process responsible for quenching the star formation. The aim of this project is to use the latest observational data shed light on this mystery, by focusing on the class of transition galaxies caught in the act of transformation. Very deep spectroscopy will provide the detailed properties of these galaxies during their transition phase (e.g. their metallicities, rates of star formation, outflow rates), while new infrared imaging from the James Webb Space Telescope (JWST) will provide unprecedented data on the morphological transformation of these galaxies, in addition to identifying those containing hidden Active Galactic Nuclei (AGN) from their characteristic hot dust emission.