Observational tests of backreaction with recent data
  We explore the backreaction model based on the template metric proposed in
Larena et al. (2008) constraining the matter density parameter $\Omega_m^{D_0}$
and the Dark Energy parameter $w$ with recent data. We provide constraints
based on Supernovae Ia from the SNLS and the Union2.1 catalogs, confirming that
the backreacted Universe should have a higher matter density than the
corresponding Friedmaniann one. Angular diameter distances from clusters data
confirm the same feature. Finally we combine these results with constraints
obtained from the position of the first three peaks and the first dip of the
CMB power spectrum, fitting WMAP-9 and Planck data. We find that an
inconsistency arises in predicting the scale factor at recombination, leading
to a backreacted Universe with lower matter density, in contradiction with
results produced by SnIa and clusters. The same behavior is confirmed by
analyzing the CMB-shift parameters from WMAP-9. We conclude exploring
qualitatively the motivations of this inconsistency.
