Star cluster formation and some implications for GAIA
  Stars form in spatially and temporarily correlated star formation events
(CSFEs) and the dynamical processes within these "embedded clusters" leave
imprints in the stellar populations in galactic fields. Such imprints are
correlations in phase space (e.g. gravitationally bound star clusters, tidal
streams), in the binary properties of stars and in the present-day stellar mass
functions in the surviving clusters. The dynamical processes include expulsion
of massive stars from cluster cores, disruption of CSFEs due to residual gas
expulsion and energy-equipartition driven evaporation of stars from clusters
leading to dark star clusters and cold kinematical streams with epicyclic
overdensities. The properties of such phase-space structures in the Milky Way
(MW) field depend on the effective gravitational potential of the MW. GAIA data
will significantly constrain all of these aspects, and will in particular
impact on gravitational dynamics via the properties of cold streams and on
star-formation via the constraint on the gas expulsion process through the
expanding unbound populations that must be associated with every CSFE.
