EPoS Contribution
EPoS Contribution
Instantaneous starburst of the massive clusters Westerlund 1 and NGC 3603 YC

Natalia Kudryavtseva
MPIA, Heidelberg, Germany
The age spread of a cluster's stellar population is a good indicator of the overall duration of the star formation process in the cluster. From multi-epoch optical and near-infrared high-angular resolution HST and adaptive optics observations of the ~5Myr old starburst cluster Westerlund 1 and ~2 Myr old starburst cluster NGC 3603 YC we derived upper limits for the age spreads of 0.4 and 0.1Myr, respectively. Our results suggest a single event for starburst cluster formation, in contradiction to previous claims that star formation in young massive clusters might have been ongoing for several 10 Myr. Our method based on a two step process. In the first step, kinematic members of the cluster were identified based on multi-epoch astrometric monitoring. In the second step, a Bayesian analysis was carried out, comparing the observed photometric sequence of cluster members with sets of theoretical isochrones. We analyzed the influence of unresolved binarity, photometric error and ongoing accretion on our result.
Wolfgang Brandner, MPIA, Germany
Mario Gennaro, MPIA, Germany
Boyke Rochau, MPIA, Germany
Andrea Stolte, AIfA, Germany
Morten Andersen, ESA, The Netherlands
Nicola Da Rio, ESA, The Netherlands
Thomas Henning, MPIA, Germany
Emanuele Tognelli, University of Pisa, Italy
David Hogg, CCPP, USA
Simon Clark, The Open University, UK
Rens Waters, API, The Netherlands