SN and BAO constraints on (new) polynomial dark energy parametrizations:
  current results and forecasts
  In this work we introduce two new polynomial parametrizations of dark energy
and explore their correlation properties. The parameters to fit are the
equation of state values at z=0 and z=0.5, which have naturally low correlation
and have already been shown to improve the popular Chevallier-Polarski-Linder
(CPL) parametrization. We test our models with low redshift astronomical
probes: type Ia supernovae and baryon acoustic oscillations (BAO), in the form
of both current and synthetic data. Specifically, we present simulations of
measurements of the radial and transversal BAO scales similar to those expected
in a BAO high precision spectroscopic redshift survey similar to EUCLID.
According to the Bayesian deviance information criterion (DIC), which penalizes
large errors and correlations, we show that our models perform better than the
CPL re-parametrization proposed by Wang (in terms of z=0 and z=0.5). This is
due to the combination of a lower correlation and smaller relative errors. The
same holds for a frequentist perspective: our Figure-of-Merit is larger for our
parametrizations.
