The latest results from the WMAP satellite [1] confirm the success of the ΛCDM model, where ∼ 75 % of the mass-energy density is in the form of dark energy, with matter, most of it in the form of cold dark matter (CDM) making up the remaining 25 % . Neutrinos with masses on the eV scale or below will be a hot component of the dark matter and will free-stream out of overdensities and thus wipe o...