Three-Component Kinematics of Multiple Stellar Populations in Globular
  Clusters with Gaia and VLT
  The internal dynamics of multiple stellar populations in Globular Clusters
(GCs) provides unique constraints on the physical processes responsible for
their formation. Specifically, the present-day kinematics of cluster stars,
such as rotation and velocity-dispersion, could be related to the initial
configuration of the system. In recent work, we provided the first study of the
kinematics of different stellar populations in NGC$\,$0104 over a large field
of view in the plane of the sky, exploiting Gaia Data Release 2 (DR2) proper
motions combined with multi-band ground-based photometry. In this paper, we
combine Gaia DR2 proper motions with Very Large Telescope radial velocities to
investigate the kinematics along the line of sight and in the plane of the sky
of multiple populations in seven GCs, namely NGC$\,$0104, NGC$\,$0288,
NGC$\,$5904, NGC$\,$6121, NGC$\,$6254, NGC$\,$6752 and NGC$\,$6838. Among the
analyzed clusters only NGC$\,$0104 and NGC$\,$5904 show significant rotation.
Separating our sample into two groups of first- and second-population stars (1P
and 2P) we find that overall these two populations exhibit a similar rotation
pattern in NGC$\,$0104. However, some hints of different rotation are observed
in the external regions of this cluster. Interestingly, 1P and 2P stars in
NGC$\,$5904 show different rotation curves, with distinct phases and such
difference is significant at the $\sim$2.5-$\sigma$ level. The analysis of the
velocity-dispersion profiles of multiple populations confirms that 2P stars of
NGC$\,$0104 show stronger anisotropy than the 1P.
