Forecasting neutrino masses from galaxy clustering in the Dark Energy Survey combined with the Planck Measurements

TL;DR

This study demonstrates that combining data from the Dark Energy Survey and Planck can significantly improve constraints on neutrino masses, potentially detecting masses greater than 0.1 eV with high confidence.

Contribution

It presents a novel combined analysis of galaxy clustering and CMB data to improve neutrino mass constraints, highlighting the importance of galaxy bias knowledge.

Findings

DES & Planck can recover the fiducial neutrino mass with +-0.12 eV uncertainty.

The combined data set tightens the neutrino mass upper limit to 0.11 eV if the true mass is near zero.

The analysis is robust to non-linearities and redshift distortions but sensitive to galaxy bias assumptions.

Abstract

We study the prospects for detecting neutrino masses from the galaxy angular power spectrum in photometric redshift shells of the Dark Energy Survey (DES) over a volume of 20 (Gpc/h)^3 combined with the Cosmic Microwave Background (CMB) angular fluctuations expected to be measured from the Planck satellite. We find that for a Lambda-CDM concordance model with 7 free parameters in addition to a fiducial neutrino mass of M_nu = 0.24 eV, we recover from DES &Planck the correct value with uncertainty of +- 0.12 eV (95 % CL), assuming perfect knowledge of the galaxy biasing. If the fiducial total mass is close to zero, then the upper limit is 0.11 eV (95 % CL). This upper limit from DES &Planck is over 3 times tighter than using Planck alone, as DES breaks the parameter degeneracies in a CMB-only analysis. The analysis utlilizes spherical harmonics up to 300, averaged in bin of 10 to mimic the DES sky coverage. The results are similar if we supplement DES bands (grizY) with the VISTA Hemisphere Survey (VHS) near infrared band (JHK). The result is robust to uncertainties in non-linear fluctuations and redshift distortions. However, the result is sensitive to the assumed galaxy biasing schemes and it requires accurate prior knowledge of the biasing. To summarize, if the total neutrino mass in nature greater than 0.1eV, we should be able to detect it with DES &Planck, a result with great importance to fundamental Physics.