Cosmological Models

We have carefully pre-selected our cosmological models (dynamical dark energy and ΛCDM) to be in agreement with latest CMB and SNIa data. For this purpose we have performed a likelihood analysis of the combined Supernova Ia UNION data set and Wilkinson Microwave Anisotropy Probe 5-yr data to identify realistic cosmologic models.

For SNIa we have developped « darkcosmos », a code to compute cosmological evolution of background quantities for several cosmologies. For CMB, we have modified CAMB (Lewis et al, 1999) in order to take into account the fluctuations of dark energy in quintessence models. This work is described in great details in Alimi et al, 2010 (section 2  « Quintessential Cosmology »). Here we summarize the cosmological parameters used in the Dark Energy Universe Simulation Series (DEUSS).

Cosmological parameters in DEUSS. Ωm is the matter density, α the slope of the quintessence potential, As the power spectrum normalisation, σ8 the variance in 8 Mpc/h sphere, λ the normalisation of the potentiel, w0 and w1 the linear equation of state parameters (not used). In all the models, the optical depth τ=0.087

All cosmologies reproduce current constraints at the homogeneous and linear level. In order to break degeneracies between dark energy models, we would like to find new probe of dark energy properties in the non-linear regime of structure formation.