We explore the properties of dark energy from recent observational data, including the Gold Sne Ia, the baryonic acoustic oscillation peak from SDSS, the CMB shift parameter from WMAP3, the X-ray gas mass fraction in cluster and the Hubble parameter versus redshift. The $\Lambda CDM$ model with curvature and two parameterized dark energy models are studied. For the $\Lambda CDM$ model, we find that the flat universe is consistent with observations at the $1\sigma$ confidence level and a closed universe is slightly favored by these data. For two parameterized dark energy models, with the prior given on the present matter density, $\Omega_{ m0}$, with $\Omega_{ m0}=0.24$, $\Omega_{ m0}=0.28$ and $\Omega_{ m0}=0.32$, our result seems to suggest that the trend of $\Omega_{ m0}$ dependence for an evolving dark energy from a combination of the observational data sets is model-dependent.
Categories: astro-ph