Do current cosmological observations rule out all Covariant Galileons?
  We revisit the cosmology of Covariant Galileon gravity in view of the most
recent cosmological data sets, including weak lensing. As a higher derivative
theory, Covariant Galileon models do not have a $\Lambda$CDM limit and predict
a very different structure formation pattern compared with the standard
$\Lambda$CDM scenario. Previous cosmological analyses suggest that this model
is marginally disfavoured, yet can not be completely ruled out. In this work we
use a more recent and extended combination of data, and we allow for more
freedom in the cosmology, by including a massive neutrino sector with three
different mass hierarchies. We use the Planck measurements of Cosmic Microwave
Background temperature and polarization; Baryonic Acoustic Oscillations
measurements by BOSS DR12; local measurements of $H_0$; the joint light-curve
analysis supernovae sample; and, for the first time, weak gravitational lensing
from the KiDS collaboration. We find, that in order to provide a reasonable
fit, a non-zero neutrino mass is indeed necessary, but we do not report any
sizable difference among the three neutrino hierarchies. Finally, the
comparison of the Bayesian Evidence to the $\Lambda$CDM one shows that in all
the cases considered, Covariant Galileon models are statistically ruled out by
cosmological data.
