Nuw CDM cosmology from the weak lensing convergence PDF

TL;DR

This paper develops a first-principles theoretical model for the weak lensing convergence PDF, validates it against simulations, and demonstrates its strong potential for constraining neutrino mass and dark energy parameters in upcoming surveys.

Contribution

It introduces a comprehensive, validated model for the convergence PDF that enables accurate cosmological parameter forecasts without relying on costly N-body simulations.

Findings

Convergence PDF model achieves percent-level accuracy against simulations.

The PDF provides stronger constraints on neutrino mass and dark energy than the two-point function.

Combining PDF with CMB priors improves parameter constraints significantly.

Abstract

Pinning down the total neutrino mass and the dark energy equation of state is a key aim for upcoming galaxy surveys. Weak lensing is a unique probe of the total matter distribution whose non-Gaussian statistics can be quantified by the one-point probability distribution function (PDF) of the lensing convergence. We calculate the convergence PDF on mildly non-linear scales from first principles using large-deviation statistics, accounting for dark energy and the total neutrino mass. For the first time, we comprehensively validate the cosmology-dependence of the convergence PDF model against large suites of simulated lensing maps, demonstrating its percent-level precision and accuracy. We show that fast simulation codes can provide highly accurate covariance matrices, which can be combined with the theoretical PDF model to perform forecasts and eliminate the need for relying on expensive N-body simulations. Our theoretical model allows us to perform the first forecast for the convergence PDF that varies the full set of $\Lambda$CDM parameters. Our Fisher forecasts establish that the constraining power of the convergence PDF compares favourably to the two-point correlation function for a Euclid-like survey area at a single source redshift. When combined with a CMB prior from Planck, the PDF constrains both the neutrino mass $M_\nu$ and the dark energy equation of state $w_0$ more strongly than the two-point correlation function.