Tracy Webb

Associate Professor

Department of Physics

McGill University

Host: Yuanyuan Su

Title: Witnessing the evolution of the most massive galaxies in the densest regions of the universe

Abstract: An understanding of the formation and evolution of massive galaxies is a forefront goal of astrophysics today, observationally and theoretically. While we generally understand structure growth in the context of CDM hierarchical structure formation, and indeed this idea has been highly successful, new observations have shown that baryonic physics plays a key role. Indeed, the complex physics of galaxy-galaxy mergers, large scale gas cooling, and AGN feeding and feedback drive the evolution of massive galaxies. Given that at any given cosmic epoch the most massive galaxies tend to be found in over dense regions of the universe, one way to observationally find and study these systems is through a search for such peaks. In this talk I will describe, after introducing the field, an ongoing observational program to understand the evolutionary growth of massive galaxies that sit at the centres of giant galaxy clusters. With a focus on key systems and multiwaveIength data, I will argue that we do not yet fully understand how these giant beasts build up their stellar mass, but that progress is being made through efforts to push our observations to earlier epochs with new tools.