Quiescent Galaxies through the Ages

Brad Holden

UC Santa Cruz

Massive galaxies in the local universe have minimal star-formation and are round, dispersion supported systems. Such galaxies are unlike the majority of the galaxy population, which shows significant star-formation and generally rotational support. In a CDM universe, such systems are expected to be assembled by the accretion of smaller mass systems along with the occasional equal mass merger. Such dynamical processes could impact the structural properties of galaxies, transforming them from more rotationally dominated systems into rounder and dispersion dominated ones. I will show evidence of structural evolution in the quiescent galaxy population, through the growth of the sizes of quiescent galaxies. Finally, I will show indirect evidence, through multiple independent measurements, that minor merging is fueling the size growth.