A new upper limit on the total neutrino mass from the 2dF Galaxy Redshift Survey

TL;DR

This work constrain f(nu) identical with Omega(nu)/Omega(m), the fractional contribution of neutrinos to the total mass density in the Universe, by comparing the power spectrum of fluctuations derived from the 2 Degree Field Galaxy Redshift Survey with power spectra for models with four components: baryons, cold dark matter, massive neutrino, and a cosmological constant.

Abstract

We constrain f_nu = Omega_nu / Omega_m, the fractional contribution of neutrinos to the total mass density in the Universe, by comparing the power spectrum of fluctuations derived from the 2dF Galaxy Redshift Survey with power spectra for models with four components: baryons, cold dark matter, massive neutrinos and a cosmological constant. Adding constraints from independent cosmological probes we find f_nu < 0.13 (at 95% confidence) for a prior of 0.1< Omega_m <0.5, and assuming the scalar spectral index n=1. This translates to an upper limit on the total neutrino mass and m_nu,tot < 1.8 eV for "concordance" values of Omega_m and the Hubble constant. Very similar results are obtained with a prior on Omega_m from Type Ia supernovae surveys, and with marginalization over n.

Figures (3)

• Figure 1: Power spectra for $\Omega_\nu = 0$ (solid line), $\Omega_\nu=0.01$ (dashed line), and $\Omega_\nu=0.05$ (dot-dashed line) with amplitudes fitted to the 2dFGRS power spectrum data (vertical bars) in redshift space. We have fixed $\Omega_{\rm m}=0.3$, $\Omega_\Lambda=0.7$, $h=0.7$, $\Omega_{\rm b}h^2=0.02$. The vertical dashed lines limit the range in $k$ used in the fits.
• Figure 2: 68 (solid line), 95 (dashed line) and 99% (dotted line) confidence contours in the plane of $f_\nu\equiv \Omega_{\nu}/\Omega_{\rm m}$ and $\Gamma\equiv\Omega_{\rm m} h$, with marginalization over $h$ and $\Omega_{\rm b}h^2$ using Gaussian priors, and over $A$ using a uniform prior in $0.5 < A < 10$. The left panel shows the case of no prior on $\Omega_{\rm m}$, and the right panel the case of a uniform 'top hat' prior on $\Omega_{\rm m}$ in $0.1<\Omega_{\rm m} < 0.5$.
• Figure 3: Probability distributions, normalized so that the area under each curve is equal to one, for $f_\nu$ with marginalization over the other parameters, as explained in the text, for $N_\nu =3$ massive neutrinos and $n=0.9$ (dotted line), $1.0$ (solid line), and $1.1$ (dashed line).