Neutrino physics from future weak lensing surveys

TL;DR

Future weak lensing surveys can detect signatures of additional neutrino species and significant neutrino masses through deviations in the shear power spectrum, providing insights beyond current cosmological constraints.

Contribution

This paper analyzes how upcoming weak lensing data can reveal neutrino properties, highlighting the potential to detect extra species or large masses independent of flatness assumptions.

Findings

Shear deficits of 20-40% or excesses of 20-60% cannot be explained by current flat LambdaCDM variations.

Detection of such shear deviations would indicate large neutrino masses or extra neutrino species.

Predictions are robust against changes in cosmic acceleration physics.

Abstract

Given recent indications of additional neutrino species and cosmologically significant neutrino masses, we analyze their signatures in the weak lensing shear power spectrum. We find that a shear deficit in the 20-40% range or excess in the 20-60% range cannot be explained by variations in parameters of the flat LambdaCDM model that are allowed by current observations of the expansion history from Type Ia supernovae, baryon acoustic oscillations, and local measures of the Hubble constant H_0, coupled with observations of the cosmic microwave background from WMAP9 and the SPT 2500 square degree survey. Hence such a shear deficit or excess would indicate large masses or extra species, respectively, and we find this to be independent of the flatness assumption. We also discuss the robustness of these predictions to cosmic acceleration physics and the means by which shear degeneracies in joint variation of mass and species can be broken.