Constraints on Simplified Quartessence Cosmology from the Latest Observational Data

Abstract

The simplified generalized Chaplygin gas (GCG) model as a candidate of UDME is studied in this paper. By using the latest 162 ESSENCE type Ia supernovae (Sne Ia) data, 30 high red shift Sne Ia data and the distance ratio from z = 0.35 to z = 1089 (the red shift of decoupling), we obtain Ω _k = 0.076_-0.077^+0.093 and α = 0.90_-0.07^+0.04 at a 95.4% confidence level. In addition the deceleration parameter for this simplified GCG model is investigated, and we find that the universe, at a 1σ confidence level, enters the acceleration era at the red shift z_{q = 0} 0.53 - 0.66 and possesses an acceleration -q_{z = 0} 0.66 - 0.78 at present.