The Radiation Budget of the Universe

This work sets bounds on the radiation content of the Universe and neutrino properties by using the WMAP‐7 year CMB measurements complemented with most of the existing CMB and LSS data, imposing also self‐consistent BBN constraints on the primordial helium abundance, Yp. Lepton asymmetric cosmological models are considered, parametrized by the neutrino degeneracy parameter ξν and the variation of the relativistic degrees of freedom, ΔNeffoth, due to possible other physical processes occurred between BBN and structure formation epochs. The results bring an important improvement over the same parameters obtained by using the WMAP data alone, showing that the LSS measurements are useful tools in constraining the radiation content of the Universe during BBN.