4/26/15: SO/NOAO Joint Colloquium Series: Rachel Bezanson

Rachel Bezanson, Steward Observatory
The Surprisingly Complex Lives of Massive Galaxies and the Stability of the Mass Fundamental Plane

Abstract:
Once thought to be relics of a much earlier epoch, the most massive local galaxies are red and dead ellipticals, with little ongoing star formation or organized rotation. In the last decade, observations of their assumed progenitors have demonstrated that the evolutionary histories of massive galaxies have been far from static. Instead, billions of years ago, massive galaxies were more compact and morphologically different, possibly with more disk-like structures and many were still forming stars. The details of this observed evolution can place constraints on the physical processes that have driven massive galaxy evolution through cosmic time. I will discuss recent observational studies of the structural and dynamical properties of massive high-redshift galaxies. Specifically, I will demonstrate that in spite of their dramatic structural evolution, the mass fundamental plane, or the empirical relation between dynamics, sizes, stellar mass surface density of massive galaxies, has been in place since z~2. This relation appears to hold for massive galaxies of all types, not just red, dead ellipticals. Therefore, this scaling relation is an ideal tool to follow the evolution of galaxy populations as it is minimally susceptible to progenitor biases due to the evolving stellar populations, structures, and dynamics of galaxies through cosmic time.