How Universal are the Young Cluster Sequences? - the Cases of LMC, SMC,
  M83 and the Antennae
  Aims.Recently a new analysis of cluster observations in the Milky Way found
evidence that clustered star formation may work under tight constraints with
respect to cluster size and density, implying the presence of just two
sequences of young massive cluster. These two types of clusters each expand at
different rates with cluster age. Methods. Here we investigate whether similar
sequences exist in other nearby galaxies. Results:We find that while for the
extragalactic young stellar clusters the overall trend in the cluster-density
scaling is quite comparable to the relation obtained for Galactic clusters,
there are also possible difference. For the LMC and SMC clusters the densities
are below the Galactic data points and/or the core radii are smaller than those
of data points with comparable density. For M83 and the Antenna clusters the
core radii are possibly comparable to the Galactic clusters but it is not clear
whether they exhibit similar expansion speeds. These findings should serve as
an incentive to perform more systematic observations and analysis to answer the
question of a possible similarity between young galactic and extragalactic star
clusters sequences.
