Modelling dust extinction in the Magellanic Clouds
  We model the extinction profiles observed in the Small and Large Magellanic
clouds with a synthetic population of dust grains consisting by core-mantle
particles and a collection of free-flying polycyclic aromatic hydrocarbons. All
different flavors of the extinction curves observed in the Magellanic Clouds
can be described by the present model, that has been previously (successfully)
applied to a large sample of diffuse and translucent lines of sight in the
Milky Way. We find that in the Magellanic Clouds the extinction produced by
classic grains is generally larger than absorption by polycyclic aromatic
hydrocarbons. Within this model, the non-linear far-UV rise is accounted for by
polycyclic aromatic hydrocarbons, whose presence in turn is always associated
to a gap in the size distribution of classical particles. This hints either a
physical connection between (e.g., a common cause for) polycyclic aromatic
hydrocarbons and the absence of middle-sized dust particles, or the need for an
additional component in the model, that can account for the non-linear far-UV
rise without contributing to the UV bump at $\sim$217 nm, e.g., nanodiamonds.
