Hierarchical structures in the Large and Small Magellanic Clouds
  We investigate the degree of spatial correlation among extended structures in
the LMC and SMC. To this purpose we work with sub-samples characterised by
different properties such as age and size, taken from the updated catalogue of
Bica et al. or gathered in the present work. The structures are classified as
star clusters or non-clusters (basically, nebular complexes and their stellar
associations). The radius distribution functions follow power-laws
($dN/dR\propto R^{-\alpha}$) with slopes and maximum radius ($R_{max}$) that
depend on object class (and age). Non-clusters are characterised by
$\alpha\approx1.9$ and $R_{max}\la472$ pc, while young clusters (age $\la10$
Myr) have $\alpha\approx3.6$ and $R_{max}\la15$ pc, and old ones (age $\ga600$
Myr) have $\alpha\approx2.5$ and $R_{max}\la40$ pc. Young clusters present a
high degree of spatial self-correlation and, especially, correlate with
star-forming structures, which does not occur with the old ones. This is
consistent with the old clusters having been heavily mixed up, since their ages
correspond to several LMC and SMC crossing times. On the other hand, with ages
corresponding to fractions of the respective crossing times, the young clusters
still trace most of their birthplace structural pattern. Also, small clusters
($R<10$ pc), as well as small non-clusters ($R<100$ pc), are spatially
self-correlated, while their large counterparts of both classes are not. The
above results are consistent with a hierarchical star-formation scenario for
the LMC and SMC.
