Physics Colloquium - February 28, 2013

Rotation, tides, and pressure anisotropy: new dynamical models for globular clusters

Abstract: Globular clusters represent an ideal “laboratory” for the study of stellar dynamics since they are compact groups of about a million stars held together by their mutual gravitational attraction, with a high density in the central regions. The great progress recently made in the acquisition of detailed information on the structure and kinematics of star clusters as well as the improvements in computational speed of the codes for performing N-body simulations call for a renewed effort in theoretical modeling, beyond the traditional paradigm that primarily relies on spherical non-rotating models of quasi-relaxed stellar systems. Driven by these motivations, I will present a number of new families of dynamical models in which important physical ingredients such as the three-dimensional effects of external tides, internal rotation, and anisotropy in velocity space, are properly taken into account. Within this new dynamical framework, supplemented by specifically designed N-body simulations, several observational and theoretical key issues can be addressed, including the study of the role of angular momentum in the early stages of star clusters formation, the dynamical interplay between angular momentum transport and two-body relaxation processes, and the kinematical characterization of globular clusters with multiple stellar populations.

Anna Lisa Varri
Department of Astronomy
Indiana University