We report results on the kinematics of Milky Way ( MW ) globular clusters ( GCs ) based on updated space velocities for nearly the entire GC population .
We found that a 3D space with the semi-major axis , the eccentricity and the inclination of the orbit with respect to the MW plane as its axes is helpful in order to dig into the formation of the GC system .
We find that GCs formed in-situ show a clear correlation between their eccentricities and their orbital inclination in the sense that clusters with large eccentricities also have large inclinations .
These GCs also show a correlation between their distance to the MW center and their eccentricity .
Accreted GCs do not exhibit a relationship between eccentricity and inclination , but span a wide variety of inclinations at eccentricities larger than \sim 0.5 .
Finally , we computed the velocity anisotropy \beta of the GC system and found for GCs formed in-situ that \beta decreases from \approx 0.8 down to 0.3 from the outermost regions towards the MW center , but remains fairly constant ( 0.7-0.9 ) for accreted ones .
These findings can be explained if GCs formed from gas that collapsed radially in the outskirts , with preference for relative high infall angles .
As the material reached the rotating forming disk , it became more circular and moved with lower inclination relative to the disk .
A half of the GC population was accreted and deposited in orbits covering the entire range of energies from the outer halo to the bulge .