Rotating Globular Clusters
  Internal rotation is considered to play a major role in the dynamics of some
globular clusters. However, in only few cases it has been studied by
quantitative application of realistic and physically justified global models.
Here we present a dynamical analysis of the photometry and three-dimensional
kinematics of omega Cen, 47 Tuc, and M15, by means of a recently introduced
family of self-consistent axisymmetric rotating models. The three clusters,
characterized by different relaxation conditions, show evidence of differential
rotation and deviations from sphericity. The combination of line-of-sight
velocities and proper motions allows us to determine their internal dynamics,
predict their morphology, and estimate their dynamical distance. The
well-relaxed cluster 47 Tuc is very well interpreted by our model; internal
rotation is found to explain the observed morphology. For M15, we provide a
global model in good agreement with the data, including the central behavior of
the rotation profile and the shape of the ellipticity profile. For the
partially relaxed cluster omega Cen, the selected model reproduces the complex
three-dimensional kinematics; in particular the observed anisotropy profile,
characterized by a transition from isotropy, to weakly-radial anisotropy, and
then to tangential anisotropy in the outer parts. The discrepancy found for the
steep central gradient in the observed line-of-sight velocity dispersion
profile and for the ellipticity profile is ascribed to the condition of only
partial relaxation of this cluster and the interplay between rotation and
radial anisotropy.
