Extended Structure in Globular Clusters
Speaker: Pete Kuzma
Abstract:
Globular star clusters (GCs) are significant building blocks of the Milky Way’s (MW) Galactic halo. With typical ages of approximately 10 billion years, GCs are relics from the earliest stages of galaxy formation and are suggested to have contributed significantly to the halo assembly process. The current population of over 160 GCs may represent a mere fraction of the initial population of GCs, as the halo is rich in stars with chemical abundances suggesting they originate from GCs. An exciting development over the past 20 years has been the discovery that several MW GCs possess significantly extended structures, sometimes reaching out to a few hundred parsecs (corresponding to many half-mass radii). The types of features found range from axisymmetric tidal tails to large diffuse stellar envelopes. Such structures are indicative of mass loss, but our understanding of extended stellar structures, such as chemistry, kinematics and overall ubiquity, is currently incomplete apart from a very small sample. This is primed to change as upcoming large spectroscopic surveys commence and provide spatial coverage and depth that have been difficult to achieve until now. In this talk, I will explore the nature of extended GC structures and their role in the build-up of the Milky Way halo. I will explore before and after the Gaia revolution, both chemically and kinematically, and how future surveys will revolutionise our view of GCs and their peripheries.