The VIMOS Public Extragalactic Redshift Survey (VIPERS). Gravity test
  from the combination of redshift-space distortions and galaxy-galaxy lensing
  at $0.5 < z < 1.2$
  We carry out a joint analysis of redshift-space distortions and galaxy-galaxy
lensing, with the aim of measuring the growth rate of structure; this is a key
quantity for understanding the nature of gravity on cosmological scales and
late-time cosmic acceleration. We make use of the final VIPERS redshift survey
dataset, which maps a portion of the Universe at a redshift of $z \simeq 0.8$,
and the lensing data from the CFHTLenS survey over the same area of the sky. We
build a consistent theoretical model that combines non-linear galaxy biasing
and redshift-space distortion models, and confront it with observations. The
two probes are combined in a Bayesian maximum likelihood analysis to determine
the growth rate of structure at two redshifts $z=0.6$ and $z=0.86$. We obtain
measurements of $f\sigma_8(0.6) = 0.48 \pm 0.12$ and $f\sigma_8(0.86) = 0.48
\pm 0.10$. The additional galaxy-galaxylensing constraint alleviates galaxy
bias and $\sigma_8$ degeneracies, providing direct measurements of
$[f(0.6),\sigma_8(0.6)] = [0.93 \pm 0.22, 0.52 \pm 0.06]$ and
$f(0.86),\sigma_8(0.86)] = [0.99 \pm 0.19, 0.48 \pm 0.04]$. These measurements
are statistically consistent with a Universe where the gravitational
interactions can be described by General Relativity, although they are not yet
accurate enough to rule out some commonly considered alternatives. Finally, as
a complementary test we measure the gravitational slip parameter, $E_G$ , for
the first time at $z>0.6$. We find values of $\smash{\overline{E}_G}(0.6) =
0.16 \pm 0.09$ and $\smash{\overline{E}_G}(0.86) = 0.09 \pm 0.07$, when $E_G$
is averaged over scales above $3 h^{-1} \rm{Mpc}$. We find that our $E_G$
measurements exhibit slightly lower values than expected for standard
relativistic gravity in a {\Lambda}CDM background, although the results are
consistent within $1-2\sigma$.
