Constraints on the Neutrino Mass from SZ Surveys

TL;DR

This paper investigates how galaxy cluster counts from SZ surveys can constrain neutrino masses, showing they can achieve competitive precision compared to CMB lensing, despite uncertainties in cluster physics.

Contribution

It demonstrates that SZ cluster counts can provide competitive and complementary constraints on neutrino mass, with detailed analysis of uncertainties affecting these measurements.

Findings

PLANCK/SZ survey can measure neutrino mass with 0.06 eV uncertainty

Future CVL SZ surveys could reach 0.04 eV precision

Cluster counts are a viable complement to CMB lensing for neutrino mass constraints

Abstract

Statistical measures of galaxy clusters are sensitive to neutrino masses in the sub-eV range. We explore the possibility of using cluster number counts from the ongoing PLANCK/SZ and future cosmic-variance-limited surveys to constrain neutrino masses from CMB data alone. The precision with which the total neutrino mass can be determined from SZ number counts is limited mostly by uncertainties in the cluster mass function and intracluster gas evolution; these are explicitly accounted for in our analysis. We find that projected results from the PLANCK/SZ survey can be used to determine the total neutrino mass with a (1\sigma) uncertainty of 0.06 eV, assuming it is in the range 0.1-0.3 eV, and the survey detection limit is set at the 5\sigma significance level. Our results constitute a significant improvement on the limits expected from PLANCK/CMB lensing measurements, 0.15 eV. Based on expected results from future cosmic-variance-limited (CVL) SZ survey we predict a 1\sigma uncertainty of 0.04 eV, a level comparable to that expected when CMB lensing extraction is carried out with the same experiment. A few percent uncertainty in the mass function parameters could result in up to a factor \sim 2-3 degradation of our PLANCK and CVL forecasts. Our analysis shows that cluster number counts provide a viable complementary cosmological probe to CMB lensing constraints on the total neutrino mass.