Resolving the rapid quenching of star formation in the local Universe

ALMA | Cycle 7 | 10.7hrs | PI - K. Rowlands

One key problem in galaxy evolution is how and why galaxies stop forming stars. However, the exact mechanisms that lead to the disruption of the gas supply, the relative importance of different quenching mechanisms, and the timescales involved are still poorly understood. Post-starburst galaxies are an ideal laboratory to study the galaxy transition process as they have undergone a recent, rapid shutdown in star formation, and are expected to be devoid of cold gas. Surprisingly, many of these galaxies still host large reservoirs of molecular gas, which challenges our current picture of quenching. Recent studies of these galaxies suffered from an aperture bias - we know rapid quenching of star formation occured in some regions but we only have unresolved measurements of the molecular gas. We propose to map CO(1-0) emission at 2.5" resolution matched to optical integral field spectroscopic data from the MaNGA survey in 13 post-starburst galaxies. We will determine whether a low gas fraction in post-starburst regions is the cause of quenching, or if gas is forming stars inefficiently. Only the combination of ALMA and optical IFU observations can reveal what processes are responsible for stopping star formation in galaxies.