Evidence of a large scale positive rotation-metallicity correlation in
  the Galactic thick disk
  This study is based on high quality astrometric and spectroscopic data from
the most recent releases by Gaia and APOGEE. We select $58\,882$ thin and thick
disk red giants, in the Galactocentric (cylindrical) distance range $5 < R <
13$~kpc and within $|z| < 3$~kpc, for which full chemo-kinematical information
is available. Radial chemical gradients, $\partial \rm{[M/H]} / \partial
\rm{R}$, and rotational velocity-metallicity correlations, $\partial V_\phi /
\partial \rm{[M/H]}$, are re-derived firmly uncovering that the thick disk
velocity-metallicity correlation maintains its positiveness over the $8$~kpc
range explored. This observational result is important as it sets experimental
constraints on recent theoretical studies on the formation and evolution of the
Milky Way disk and on cosmological models of Galaxy formation.
