Proper Motions and Internal Dynamics in the Core of the Globular Cluster
  M71
  We have used Gemini North together with the NIRI-ALTAIR adaptive optics
imager in the H and K bands to explore the core of the Galactic globular
cluster M71 (NGC 6838). We obtained proper motions for 217 stars and have
resolved its internal proper motion dispersion. Using a 3.8 year baseline, the
proper motion dispersion in the core is found to be 179 +/- 17 microarcsec/yr.
We find no evidence of anisotropy in the motions and no radial variation in the
proper motions with respect to distance from the cluster center. We also set an
upper limit on any central black hole to be ~150 Msun at 90% confidence level.
