The Observational Status Of Galileon Gravity After Planck

(1)To fully assess the observational viability of any cosmological model we must allow all of its parameters to vary within the observational constraints. This helps to understand any hidden degeneracies between the parameters that are hard to identify if one studies only a handful of parameter value combinations.This chapter builds upon the methodology described in Chap. 2. We use the modified version of the CAMB code developed there to perform a Monte Carlto Markov Chain (MCMC) exploration of the full cosmological parameter space, and not only its Galilean subspace. We place observational constraints using the CMB temperature and CMB lensing potential data from the Planck satellite [3, 4], together with BAO data at lower redshift. Here, we shall pay special attention to the role played by the summed mass of the three active neutrinos, Sigma m(v), in the constraints of the Galileon model.We start this chapter by describing our methodology. Some of it is different from the one used to obtain the results in the last chapter, namely in what concerns the treatment of the background evolution. For clarity, we shall therefore be careful at justifying the steps we follow to constrain the Galileon model.