Exploring hints for dark energy density evolution in light of recent   data
  Considering a quadratic parametrization of the dark energy density, we explore signatures of evolution using data from gas mass fraction in clusters, type Ia supernova, BAO and CMB. We find -- excluding CMB data -- a preference for a evolution of $\rho_{de}(z)$ towards smaller values as redshift increases, a result consistent with a recent study using the BAO DR11 data by Delubac et al. (2015). 
Victor H. Cardenas
astro-ph.CO gr-qc