as tr o - ph / 9 50 60 42 6 Ju n 95 DYNAMICS OF THE GALACTIC GLOBULAR CLUSTER NGC 3201

BV CCD frames have been used to derive surface brightness pro les for NGC 3201 which extend out to approximately 180. A total of 857 radial velocities with median precision ' 1 km s 1 for 399 member giants have been used to trace the velocity dispersion pro le out to 32.10 (the approximate tidal radius determined from ts of single-mass, isotropic King-Michie models to the cluster surface brightness pro les). The median difference in radial velocity for stars on either side of an imaginary axis stepped through the cluster in 1 increments shows a statistically signi cant maximum amplitude of 1.22 0.25 km s 1. We discuss several possible explanations of this result, including: (1) cluster rotation; (2) preferential stripping of stars on prograde orbits near the limiting radius; (3) the projection of the cluster space velocity onto the plane of the sky and; (4) a slight drift in the velocity zero point. It is di cult to unambiguously identify the primary cause of the observed structure in the velocity eld, however, and we suspect that all of the above processes may play a role. The BV surface brightness pro les and radial velocities have been modeled with both singleand multi-mass King-Michie models and nonparametric techniques. The corresponding densityand M/L-pro les show good agreement over the interval 1:5 < R < 10 pc, and both approaches suggest a steady rise in M/L with distance from the cluster center. Due to the low cluster luminosity, we are unable to place useful constraints on the anisotropy of the velocity dispersion pro le, though the global mass-tolight ratio is well-constrained by the models: M/LB 'M/LV ' 2.0 0.2 for the multi-mass and nonparametric models, compared to ' 1.65 0.15 for models having equal-mass stars. Our bestt, multi-mass models have mass function slopes of x ' 0:75 0:25, consistent with recent ndings that the form of the mass function depends on the position relative to the potential of the Galaxy.