The strong rotation of M5 (NGC 5904) as seen from the MIKiS Survey of
  Galactic Globular Clusters
  In the context of the ESO-VLT Multi-Instrument Kinematic Survey (MIKiS) of
Galactic globular clusters, we present the line-of-sight rotation curve and
velocity dispersion profile of M5 (NGC 5904), as determined from the radial
velocity of more than 800 individual stars observed out to 700" (~ 5 half-mass
radii) from the center. We find one of the cleanest and most coherent rotation
patterns ever observed for globular clusters, with a very stable rotation axis
(having constant position angle of 145^o at all surveyed radii) and a
well-defined rotation curve. The density distribution turns out to be flattened
in the direction perpendicular to the rotation axis, with a maximum ellipticity
of 0.15. The rotation velocity peak (~3 km/s in projection) is observed at ~0.6
half-mass radii, and its ratio with respect to the central velocity dispersion
(~0.3-0.4 at 4 projected half-mass radii) indicates that ordered motions play a
significant dynamical role. This result strengthens the growing empirical
evidence of the kinematic complexity of Galactic globular clusters and
motivates the need of fundamental investigations of the role of angular
momentum in collisional stellar dynamics.
