A Cosmic Model Parameterizing the late Universe

Abstract

A simple speed-up cosmology model is proposed to account for the dark energy puzzle. We condense contributions from dark energy and from the curvature term into one effective parameter in order to reduce parameter degeneracies and to find any deviation from the flat concordance A Cold dark Matter (CDM) model, by considering that the discrimination between dynamical and non-dynamical sources of cosmic acceleration as the best starting point for analyzing dark energy data sets both at present and in future. We also combine recent Type Ta Supernova (SNeIa), Cosmic Microwave Background (CMB) and Baryon Acoustic Oscillation (BAO) to constrain model parameter space. Degeneracies between model parameters are discussed by using both a degeneracy diagram and a data analysis, including high redshift information from Gamma Ray Bursts (GRBs) sample. The analysis results show that our model is consistent with cosmological observations. We try to distinct the curvature effects from the specially scaling dark energy component as parameterized. We study the linear growth of large scale structure and finally show the effective dark energy equation of state in our model and how the matter component coincides numerically with the dark energy.