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.
Here we investigate whether similar sequences exist in other nearby galaxies.
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.