Conservative estimates of the mass of the neutrino from cosmology

Abstract

A range of experimental results point to the existence of a massive neutrino. The recenthigh precision measurements of the cosmic microwave background and the large scalesurveys of galaxies can be used to place an upper bound on this mass. In this paper weperform a thorough analysis of all assumptions that go into obtaining a credible limit on. In particular we explore the impact of extending parameter space beyond the currentstandard cosmological model, the importance of priors and the uncertainties due to biasingin large scale structure. We find that the mass constraints are independent of the choice ofparametrization as well as the inclusion of spatial curvature. The results of including thepossibility of dark energy and tensor perturbations are shown to depend critically on thedatasets used. The difference between an upper bound of 2.2 eV, assuming generic initialconditions, and an upper bound of 0.63 eV, assuming adiabaticity and a galaxy bias of1, demonstrate the dependence of such a constraint on the assumptions in theanalysis.