- Here is an example of some extra science you can do with large redshift surveys. We use P(k) and try to fit models with non-zero Ω
_{ν}(total neutrino mass density) and from that determine a mass for all species of neutrinos. The 2dF Team conducted such an analysis (Elgaroy et al. 2002) and their results are shown below

Elgaroy et al. and the 2dF Galaxy Redshift Survey Team (2002)

- Shown here are the probability contours from the 2dF study (see caption of image), and further below is the probability distribution for f
_{ν}= Ω_{ν}/Ω_{m}for varying primordial spectral indices n and 3 species of neutrinos (N_{ν})

T Elgaroy et al. and the 2dF Galaxy Redshift Survey Team (2002)

Elgaroy et al. and the 2dF Galaxy Redshift Survey Team (2002)

Using the n=1.0 model with 0.1 < Ω_{m} < 0.5 as a prior (i.e. concordance model), the 2dF GRS team has found:

- f
_{ν}= Ω_{ν}/Ω_{m}< 0.13 (95% confidence) - this translates into m
_{ν,tot}< 1.8 eV

*(better constraint than from particle physics)* - Marginalizing over n, the limit becomes m
_{ν,tot}< 2.2 eV