2D kinematics of massive stars near the Galactic Center
  The presence of massive stars (MSs) in the region close to the Galactic
Center (GC) poses several questions about their origin. The harsh environment
of the GC favors specific formation scenarios, each of which should imprint
characteristic kinematic features on the MSs. We present a 2D kinematic
analysis of MSs in a GC region surrounding Sgr A* based on high-precision
proper motions obtained with the Hubble Space Telescope. Thanks to a careful
data reduction, well-measured bright stars in our proper-motion catalogs have
errors better than 0.5 mas yr$^{-1}$. We discuss the absolute motion of the MSs
in the field and their motion relative to Sgr A*, the Arches and the
Quintuplet. For the majority of the MSs, we rule out any distance further than
3-4 kpc from Sgr A* using only kinematic arguments. If their membership to the
GC is confirmed, most of the isolated MSs are likely not associated with either
the Arches or Quintuplet clusters or Sgr A*. Only a few MSs have proper motions
suggesting they are likely members of the Arches cluster, in agreement with
previous spectroscopic results. Line-of-sight radial velocities and distances
are required to shed further light on the origin of most of these massive
objects. We also present an analysis of other fast-moving objects in the GC
region, finding no clear excess of high-velocity escaping stars. We make our
astro-photometric catalogs publicly available.
