WISDOM: Molecular Cloud Properties and Star-formation Quenching in Spheroids

Molecular gas is the fuel for star formation in galaxies. Using observations from the mm-Wave Interferometric Survey of Dark Object Masses (WISDOM), that spatially resolve (1-30 pc) individual molecular clouds across the Hubble sequence, I will reveal a clear dependence of the nature of the molecular interstellar medium of galaxies on Hubble type. I will then highlight the shortcomings of the usual virial approach to clouds as self-gravitating objects, and stress the importance of the external galactic potential and in-plane shear to regulate the dynamical states of clouds. I will illustrate these issues with several observations that reveal few or no clouds in regular extended molecular gas discs, and peculiar clouds properties within bars. Finally, using diverse observations of star-formation tracers, I will discuss the impact of these different mechanisms on the star-formation efficiency of clouds and thus the quenching of star formation, particularly in galaxy nuclei and spheroids (morphological quenching).