Probing dark energy with tomographic weak-lensing aperture mass statistics

¹ Aix-Marseille Univ, CNRS, CNES, LAM, Marseille, France
e-mail: nicolas.martinet@lam.fr
² Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
³ Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK
⁴ Argelander-Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, 53121 Bonn, Germany

Received: 14 October 2020
Accepted: 20 November 2020

Abstract

We forecast and optimize the cosmological power of various weak-lensing aperture mass (M_ap) map statistics for future cosmic shear surveys, including peaks, voids, and the full distribution of pixels (1D M_ap). 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 − Ω_m − w₀ parameter space. We develop a new tomographic formalism that exploits the cross-information between redshift slices (cross-M_ap) in addition to the information from individual slices (auto-M_ap) probed in the standard approach. Our auto-M_ap forecast precision is in good agreement with the recent literature on weak-lensing peak statistics and is improved by ∼50% when including cross-M_ap. It is further boosted by the use of 1D M_ap 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 M_ap 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 M_ap map statistics not only offers the potential to improve the constraints on the recent σ₈–Ω_m tension, but also constitutes an avenue to understanding the accelerated expansion of our Universe.