How do galaxies die? The causes of quenching in galaxy evolution
One of the key problems in astrophysics is understanding how and why galaxies switch off their star formation, building the “red and dead” population that we observe in the local Universe. Over the past decade, whilst large-area galaxy surveys have revolutionised our knowledge of the quiescent galaxy population and its build-up over cosmic time, the mechanisms which lead to the shutdown of star formation are still poorly understood. A popular scenario to explain quenching invokes gas-rich mergers, which may trigger a starburst, depleting the gas supply and/or preventing gas from forming stars via feedback mechanisms. Whilst stellar-driven outflows are commonly observed and may remove so! me gas, ad ditional mechanisms are required to induce a galaxy-wide shutdown in star formation by expelling all of the gas and to stop infalling gas from forming stars. In numerical simulations, energy input from an AGN is usually invoked to complete the transition of galaxies from star forming to quiescent, through gas heating or expulsion. However, direct observational evidence for such a scenario is scarce. This session will bring together observers and theorists to discuss how star formation is quenched in galaxies.

Kate Rowlands, Carolin Villforth
B9, B10. Thursday 1:30pm & 4:30pm