Globular clusters in the inner Galaxy classified from dynamical orbital
  criteria
  Globular clusters (GCs) are the most ancient stellar systems in the Milky
Way. Therefore, they play a key role in the understanding of the early chemical
and dynamical evolution of our Galaxy. Around $40\%$ of them are placed within
$\sim4$ kpc from the Galactic center. In that region, all Galactic components
overlap, making their disentanglement a challenging task. With Gaia DR2, we
have accurate absolute proper motions for the entire sample of known GCs that
have been associated with the bulge/bar region. Combining them with distances,
from RR Lyrae when available, as well as radial velocities from spectroscopy,
we can perform an orbital analysis of the sample, employing a steady Galactic
potential with a bar. We applied a clustering algorithm to the orbital
parameters apogalactic distance and the maximum vertical excursion from the
plane, in order to identify the clusters that have high probability to belong
to the bulge/bar, thick disk, inner halo, or outer halo component. We found
that $\sim 30\%$ of the clusters classified as bulge GCs based on their
location are just passing by the inner Galaxy, they appear to belong to the
inner halo or thick disk component, instead. Most of GCs that are confirmed to
be bulge GCs are not following the bar structure and are older than the epoch
of the bar formation.
