Constraints on accelerating universe using ESSENCE and Gold supernovae data combined with other cosmological probes

We use recent data: the 192 ESSENCE type Ia supernovae (SNe Ia), the 182 Gold SNe Ia, the three-year WMAP, the SDSS baryon acoustic peak, the X-ray gas mass fraction in clusters and the observational H(z) data, to constrain models of the accelerating universe. Combining the 192 ESSENCE data with the observational H(z) data to constrain the parameterized deceleration parameter, we obtain the best-fit values of the transition redshift and current deceleration parameter z T=0.632 -0.127 +0.256 and q 0=-0.788 -0.182 +0.182 . Furthermore, using the ΛCDM model and two model-independent equations of state of the dark energy, we find that the combined constraint from the 192 ESSENCE data and four other cosmological observations gives smaller values for Ω 0m and q 0, but a larger value for z T than the combined constraint from the 182 Gold data with four other observations. Finally, according to the Akaike information criterion it is shown that the recently observed data equally support three dark energy models: ΛCDM, w de(z)=w 0 and w de(z)=w 0+w 1ln∈(1+z). © 2008 Springer-Verlag / Società Italiana di Fisica.