Evidence for mixing between ICM and stripped ISM by the analysis of the
  gas metallicity in the tails of jellyfish galaxies
  Hydrodynamical simulations show that the ram-pressure stripping in galaxy
clusters fosters a strong interaction between stripped interstellar medium
(ISM) and the surrounding medium, with the possibility of intracluster medium
(ICM) cooling into cold gas clouds. Exploiting the MUSE observation of three
jellyfish galaxies from the GAs Stripping Phenomena in galaxies with MUSE
(GASP) survey, we explore the gas metallicity of star-forming clumps in their
gas tails. We find that the oxygen abundance of the stripped gas decreases as a
function of the distance from the parent galaxy disk; the observed metallicity
profiles indicate that more than 40% of the most metal-poor stripped clouds are
constituted by cooled ICM, in qualitative agreement with simulations that
predict mixing between the metal-rich ISM and the metal-poor ICM.
