Constraints on neutrino masses from the lensing dispersion of Type Ia supernovae

TL;DR

This paper explores how gravitational lensing effects on Type Ia supernovae can be used to constrain the total neutrino mass, proposing methods to improve current limits with future surveys.

Contribution

It introduces a realistic model for lensing dispersion in inhomogeneous universes and estimates neutrino mass constraints achievable with upcoming optical surveys.

Findings

Potential to constrain neutrino mass to ~1.0 eV with future surveys.

Discussion on observational requirements to reach current neutrino mass limits.

Method to account for nonlinear matter power spectrum effects of massive neutrinos.

Abstract

We investigate how accurately the total mass of neutrinos is constrained from the magnitude dispersion of SNe Ia due to the effects of gravitational lensing. For this purpose, we use the propagation equation of light bundles in a realistic inhomogeneous universe and propose a sample selection for supernovae to avoid difficulties associated with small-scale effects such as strong lensing or shear effects. With a fitting formula for the nonlinear matter power spectrum taking account of the effects of massive neutrinos, we find that in our model it is possible to obtain the upper limit $\Sigma m_{\nu} \simeq 1.0[{\rm eV}]$ for future optical imaging surveys with the Wide-Field InfraRed Survey Telescope and Large Synoptic Survey Telescope. Furthermore, we discuss how far we need to observe SNe Ia and to what extent we have to reduce the magnitude error except for lensing in order to realize the current tightest limit $\Sigma m_{\nu} < 0.2[{\rm eV}]$.