Scientific Rationale

The once commonly accepted view that all stars start their life in compact gas-embedded clusters has been increasingly challenged over the past years. Extended old globular clusters have been discovered in dwarf galaxies (Da Costa et al. 2009) and two sequences of young star clusters have been shown to co-exist in the disc of our Galaxy (Pfalzner 2009). The ability of the sole SFE~30% compact gas-embedded clusters to account for the spatial distribution of stellar structures in the Large Magellanic Cloud has been questioned (Bastian et al. 2009). These recent observations tell us that our understanding of the clustered mode of star formation may have reached a turning-point. In terms of modelling, much emphasis has so far been put on the young cluster mass function (Parmentier et al. 2008). Yet, as a cluster responds to gas expulsion, the amount of infant weight-loss it experiences - which influences the cluster mass - is closely related to its degree of spatial expansion (Baumgardt & Kroupa 2007). With the ever increasing quality of cluster half-light radius data sets (Scheepmaker et al. 2007), the time is ripe to investigate what cluster sizes can also tell us about cluster formation and early evolution.

This group meeting aims at advancing our understanding in this field by assembling experts in cluster formation and evolution, gas-embedded and gas-free clusters, observations and simulations.

Meeting Format

The adopted meeting format will largely include time for discussions. Confirmed participants are invited to submit the topics they wish to discuss during the meeting. Should they want to present an oral contribution, they can send a title and a brief explanation too, quoting whether their presentation could be used as the triggering talk of a particular topical discussion (deadline 31 January 2010).

Venue

The YSCBonn meeting will be taking place at the  Argelander-Institut für Astronomie of the University of Bonn, set in the bucolic setting of Endenich in Bonn suburb.