HEP Theory Journal Club

Observational constraints to a unified cosmological model

Rodrigo Rocha Cuzinatto

Federal University of Alfenas

We propose a phenomenological unified model for dark matter and dark energy based on an equation of state parameter w that scales with the arctan of the redshift. The free parameters of the model are three constants: Ω_b0, α and β. Cosmological parameters are fixed by observational data from Primordial Nucleosynthesis (PN), Supernovae of the type Ia (SNIa), Gamma-Ray Bursts (GRB) and Baryon Acoustic Oscillations (BAO). The calibration of the 138 GRB events is performed using the 580 SNIa of the Union2.1 data set and a new set of 79 high-redshift GRB is obtained. We use a non-standard Akima's interpolation technique in the process of calibrating the GRB curve. The various sets of data are used in different combinations to constraint the parameters through statistical analysis. The unified model is compared to the ΛCDM model and their differences are emphasized.