Reconstruction of 5D Cosmological Model From Recent Observations

We use a parameterized equation of state (EOS) of dark energy to a 5D Ricci-flat cosmological solution and suppose the universe contains two major components: dark matter and dark energy. Using the recent observational datasets: the latest 182 type Ia Supernovae Gold data, the 3-year WMAP CMB shift parameter and the SDSS baryon acoustic peak, we obtain the best fit values of the EOS and two major components' evolution. We find that the best fit EOS crossing -1 in the near past $z\simeq 0.07$, the present best fit value of $w_x(0)<-1$ and for this model the universe experiences the acceleration at about $z\simeq 0.5$.