Probing dark energy with tomographic weak-lensing aperture mass statistics

Abstract

We forecast and optimize the cosmological power of various weak-lensing aperture mass (Map) map statistics for future cosmic shear surveys, including peaks, voids, and the full distribution of pixels (1D Map). These alternative methods probe the non-Gaussian regime of the matter distribution, adding complementary cosmological information to the classical two-point estimators. Based on the SLICS and cosmo-SLICS N-body simulations, we build Euclid-like mocks to explore the S8 − Ωm − w0 parameter space. We develop a new tomographic formalism that exploits the cross-information between redshift slices (cross-Map) in addition to the information from individual slices (auto-Map) probed in the standard approach. Our auto-Map forecast precision is in good agreement with the recent literature on weak-lensing peak statistics and is improved by ∼50% when including cross-Map. It is further boosted by the use of 1D Map that outperforms all other estimators, including the shear two-point correlation function (γ-2PCF). When considering all tomographic terms, our uncertainty range on the structure growth parameter S8 is enhanced by ∼45% (almost twice better) when combining 1D Map and the γ-2PCF compared to the γ-2PCF alone. We additionally measure the first combined forecasts on the dark energy equation of state w0, finding a factor of three reduction in the statistical error compared to the γ-2PCF alone. This demonstrates that the complementary cosmological information explored by non-Gaussian Map map statistics not only offers the potential to improve the constraints on the recent σ8–Ωm tension, but also constitutes an avenue to understanding the accelerated expansion of our Universe.