The young star cluster population of M51 with LEGUS - II. Testing
  environmental dependencies
  It has recently been established that the properties of young star clusters
(YSCs) can vary as a function of the galactic environment in which they are
found. We use the cluster catalogue produced by the Legacy Extragalactic UV
Survey (LEGUS) collaboration to investigate cluster properties in the spiral
galaxy M51. We analyse the cluster population as a function of galactocentric
distance and in arm and inter-arm regions. The cluster mass function exhibits a
similar shape at all radial bins, described by a power law with a slope close
to $-2$ and an exponential truncation around $10^5\ \rm{M}_{\odot}$ . While the
mass functions of the YSCs in the spiral arm and inter-arm regions have similar
truncation masses, the inter-arm region mass function has a significantly
steeper slope than the one in the arm region; a trend that is also observed in
the giant molecular cloud mass function and predicted by simulations. The age
distribution of clusters is dependent on the region considered, and is
consistent with rapid disruption only in dense regions, while little disruption
is observed at large galactocentric distances and in the inter-arm region. The
fraction of stars forming in clusters does not show radial variations, despite
the drop in the $H_2$ surface density measured as function of galactocentric
distance. We suggest that the higher disruption rate observed in the inner part
of the galaxy is likely at the origin of the observed flat cluster formation
efficiency radial profile.
