Thomas H. Puzia
Herzberg Institute of Astrophysics
Victoria, BC

Abstract

Extragalactic Globular Cluster Systems: The Swiss-Army Knives of Astrophysics

Globular Clusters are the best approximations to simple stellar populations known to exist. Compared to the complex stellar population mix of the diffuse (i.e. unresolved) light of their host galaxies, the integrated light of globular clusters can be reliably compared to population synthesis model predictions. Given that globular clusters exist in virtually every galaxy and form during major star formation episodes, they can be used as tracer populations of star formation and assembly histories of their host galaxies. In my talk, I will recapitulate evidence for the presence of multiple globular cluster sub-populations in the Local Group. Moving on to more massive systems, I will also present recent advance in modeling the chemical composition distributions of globular cluster systems in massive elliptical galaxies that appear to be consistent with the monolithic collapse formation scenario. The comparison of model predictions with spectroscopic observations reveals the presence of a new, super metal-rich globular cluster population that is likely to exist only in the most massive galaxies. Furthermore, there is strong evidence for multiple enrichment epochs/mechanisms of the ancient globular cluster sub-population the formation of which likely predates the formation epoch of the vast majority of stars in elliptical galaxies. I will discuss these results, in particular in the context of hierarchical galaxy formation.

Please come meet the speaker over refreshments from 3:45-4:10pm in the foyer on floor G above the lecture hall. All Welcome Host: Guy Worthey