Probing the cosmic acceleration history and the properties of dark energy from theESSENCE supernova data with a model independent method

Abstract

With a model independent method the expansion historyH(z), the decelerationparameter q(z) of the universe and the equation of statew(z) for the dark energy are reconstructed directly from the 192 Sne Ia (type Ia supernovae) datapoints which are contained in the new ESSENCE (Equation of State: Supernovae Trace CosmicExpansion) Sne Ia data and the high redshift Sne Ia data. We find that the evolving properties ofq(z) and w(z) reconstructed from the 192 Sne Ia data seem to be weaker than those obtained from the Goldset, but stronger than those from the SNLS (Supernova Legacy Survey) set. With a combinationof the 192 Sne Ia and BAO (Baryonic Acoustic Oscillation) data, a tight constraint onΩm0 is obtained.At the 1σ confidence level Ωm0 = 0.278−0.023+0.024, which is highly consistent with the values from theGold + BAO and SNLS + BAO data.