Letter to the Editor

Starlet higher order statistics for galaxy clustering and weak lensing

¹ Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, 91191 Gif-sur-Yvette, France
² Institute for Particle Physics and Astrophysics, Department of Physics, ETH Zürich, Wolfgang Pauli Strasse 27, 8093 Zürich, Switzerland
e-mail: vajani@phys.ethz.ch
³ School of Mathematics, Statistics and Physics, Newcastle University, Herschel Building, NE1 7RU Newcastle-upon-Tyne, UK

Received: 18 November 2022
Accepted: 15 March 2023

Abstract

We present a first application to photometric galaxy clustering and weak lensing of wavelet-based multi-scale (beyond two points) summary statistics: starlet peak counts and starlet ℓ₁-norm. Peak counts are the local maxima in the map, and ℓ₁-norm is computed via the sum of the absolute values of the starlet (wavelet) decomposition coefficients of a map, providing a fast multi-scale calculation of the pixel distribution, encoding the information of all pixels in the map. We employ the cosmo-SLICS simulations sources and lens catalogues, and we compute wavelet-based non-Gaussian statistics in the context of combined probes and their potential when applied to the weak-lensing convergence maps and galaxy maps. We obtain forecasts on the matter density parameter Ω_m, the reduced Hubble constant h, the matter fluctuation amplitude σ₈, and the dark energy equation of state parameter w₀. In our setting for this first application, we consider the two probes to be independent. We find that the starlet peaks and the ℓ₁-norm represent interesting summary statistics that can improve the constraints with respect to the power spectrum, even in the case of photometric galaxy clustering and when the two probes are combined.