Compact star clusters in M51 with HST

The age distribution of the clusters declines starting at very young ages, and can be represented by a power law, dN/d{tau}{propto}{tau}^gamma^, with {gamma}=-0.65+/-0.15. No significant changes in the shape of the age distribution at different masses is observed.

The mass function of the clusters younger than {tau}~400Myr can also be described by a power law, dN/dM{propto}M^{beta}^, with {beta}~-2.1+/-0.2. We compare these distributions with the predictions from various cluster disruption models, and find that they are consistent with models where clusters disrupt approximately independent of their initial mass, but not with models where lower mass clusters are disrupted earlier than their higher mass counterparts.