An improved limit on the neutrino mass with CMB and redshift-dependent halo bias-mass relations from SDSS, DEEP2, and Lyman-Break Galaxies

TL;DR

This study combines galaxy bias measurements at multiple redshifts with CMB data to tighten constraints on neutrino masses and dark energy properties, achieving the most stringent limits to date.

Contribution

It introduces a novel analysis of luminosity-dependent galaxy bias across redshifts to improve constraints on neutrino mass and dark energy parameters.

Findings

Upper limit on neutrino mass: <0.28 eV (95% CL)

Dark energy equation of state: w=-1.30±0.19

Enhanced constraints with combined datasets

Abstract

We use measurements of luminosity-dependent galaxy bias at several different redshifts, SDSS at $z=0.05$, DEEP2 at $z=1$ and LBGs at $z=3.8$, combined with WMAP five-year cosmic microwave background anisotropy data and SDSS Red Luminous Galaxy survey three-dimensional clustering power spectrum to put constraints on cosmological parameters. Fitting this combined dataset, we show that the luminosity-dependent bias data that probe the relation between halo bias and halo mass and its redshift evolution are very sensitive to sum of the neutrino masses: in particular we obtain the upper limit of $\sum m_{\nu}<0.28$eV at the 95% confidence level for a $\Lambda CDM + m_{\nu}$ model, with a $\sigma_8$ equal to $\sigma_8=0.759\pm0.025$ (1$\sigma$). When we allow the dark energy equation of state parameter $w$ to vary we find $w=-1.30\pm0.19$ for a general $wCDM+m_{\nu}$ model with the 95% confidence level upper limit on the neutrino masses at $\sum m_{\nu}<0.59$eV. The constraint on the dark energy equation of state further improves to $w=-1.125\pm0.092$ when using also ACBAR and supernovae Union data, in addition to above, with a prior on the Hubble constant from the Hubble Space Telescope.