Abstract

In the 1920s Hubble recognised that massive galaxies exist in predominantly two types – spirals or ellipticals. It was also recognised very early on that elliptical galaxies are typically “dead”, they have very little ongoing star formation linked to very low cold gas and dust contents, while spiral galaxies have more cold gas and are still forming stars. One of the biggest open questions in extragalactic astronomy is what causes some galaxies to shut off their star formation, potentially with a concurrent morphological transformation, while others don’t. Our ability to quantify the changing demographics of the galaxy population has progressed substantially in the last couple of decades, thanks to large multiwavelength and spectroscopic surveys probing ever deeper into the Universe. However, we still can’t pinpoint exactly what processes are responsible for this galaxy transformation. I will present our recent work on post-starburst galaxies, one type of transition galaxy that provides clues about how star formation might have quenched in a significant fraction of the galaxy population.