Legacy ExtraGalactic UV Survey with The Hubble Space Telescope. Stellar
  cluster catalogues and first insights into cluster formation and evolution in
  NGC 628
  We report the large effort which is producing comprehensive high-level young
star cluster (YSC) catalogues for a significant fraction of galaxies observed
with the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. We
present the methodology developed to extract cluster positions, verify their
genuine nature, produce multiband photometry (from NUV to NIR), and derive
their physical properties via spectral energy distribution fitting analyses. We
use the nearby spiral galaxy NGC628 as a test case for demonstrating the impact
that LEGUS will have on our understanding of the formation and evolution of
YSCs and compact stellar associations within their host galaxy. Our analysis of
the cluster luminosity function from the UV to the NIR finds a steepening at
the bright end and at all wavelengths suggesting a dearth of luminous clusters.
The cluster mass function of NGC628 is consistent with a power-law distribution
of slopes $\sim -2$ and a truncation of a few times $10^5$ M$_\odot$. After
their formation YSCs and compact associations follow different evolutionary
paths. YSCs survive for a longer timeframe, confirming their being potentially
bound systems. Associations disappear on time scales comparable to
hierarchically organized star-forming regions, suggesting that they are
expanding systems. We find mass-independent cluster disruption in the inner
region of NGC628, while in the outer part of the galaxy there is little or no
disruption. We observe faster disruption rates for low mass ($\leq$ $10^4$
M$_\odot$) clusters suggesting that a mass-dependent component is necessary to
fully describe the YSC disruption process in NGC628.
