Towards a physical picture of star formation quenching: the photometric properties of recently quenched galaxies in the Sloan Digital Sky Survey

We select a sample of young passive galaxies from the Sloan Digital Sky Survey Data Release 7 in order to study the processes that quench star formation in the local universe. Quenched galaxies are identified based on the contribution of A-type stars to their observed (central) spectra and relative lack of ongoing star formation; we find that such systems account for roughly 2.5 per cent of all galaxies with log (M=M ) > 9:5, and have a space density of 2:2 10 4 Mpc 3 . We show that quenched galaxies span a range of morphologies, but that visual classifications suggest they are predominantly early-type systems. Their visual early