New constraints on Coupled Dark Energy from Planck
  We present new constraints on coupled dark energy from the recent
measurements of the Cosmic Microwave Background Anisotropies from the Planck
satellite mission. We found that a coupled dark energy model is fully
compatible with the Planck measurements, deriving a weak bound on the dark
matter-dark energy coupling parameter \xi=-0.49^{+0.19}_{-0.31} at 68% c.l..
Moreover if Planck data are fitted to a coupled dark energy scenario, the
constraint on the Hubble constant is relaxed to H_0=72.1^{+3.2}_{-2.3}
km/s/Mpc, solving the tension with the Hubble Space Telescope value. We show
that a combined Planck+HST analysis provides significant evidence for coupled
dark energy finding a non-zero value for the coupling parameter \xi, with
-0.90< \xi <-0.22 at 95% c.l.. We also consider the combined constraints from
the Planck data plus the BAO measurements of the 6dF Galaxy Survey, the Sloan
Digital Sky Survey and the Baron Oscillation Spectroscopic Survey.
