The Life-Cycle of Gas in Dying Galaxies
Modern day galaxies
populate a bimodal distribution, in both morphology and color space. Their
morphological and color properties are also inter-related, with lenticular and
elliptical galaxies usually exhibiting red colors and spiral galaxies usually
exhibiting blue colors. In color space, there is a genuine dearth of
intermediate colored galaxies, suggesting that the transition a galaxy
undergoes to transform must be rapid, and quenching galaxies, rare. Gas - its
presence, absence, and mechanics - serves as the anchor of a galaxy's
transformation from blue to red. I will discuss the nature of gas in
transitioning and transitioned galaxies through two lenses: (1) How a galaxy
transition is able to impact the behavior of molecular gas, and (2) how new
observations of molecular gas in quenching and quenched galaxies has recast our
understanding of how they ultimately metamorphose from blue, star-forming
spirals into red, quiescent ellipticals and lenticulars.