Star cluster formation and some implications for GAIA

TL;DR

This paper discusses how star formation in clusters leaves observable imprints in stellar populations and how GAIA data can help constrain models of these processes and their effects on galactic dynamics.

Contribution

It highlights the potential of GAIA data to improve understanding of star formation, cluster disruption, and phase-space structures in the Milky Way.

Findings

GAIA will constrain star formation and cluster disruption models.

Phase-space structures depend on the Milky Way's gravitational potential.

GAIA data will impact understanding of gravitational dynamics and star formation processes.

Abstract

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.