Persistent homology in cosmic shear

II. A tomographic analysis of DES-Y1

¹ Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany
e-mail: sven@astro.uni-bonn.de
² ETH Zürich, Department of Mathematical Sciences, Rämistrasse 101, 8092 Zürich, Switzerland
³ School of Mathematics, Statistics and Physics, Newcastle University, Herschel Building, NE1 7RU Newcastle-upon-Tyne, UK
⁴ Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK
⁵ Ruhr University Bochum, Faculty of Physics and Astronomy, Astronomical Institute (AIRUB), German Centre for Cosmological Lensing, 44780 Bochum, Germany
⁶ Osservatorio Astronomico di Trieste, via Tiepolo 11, 34131 Trieste, Italy
⁷ Institute for Fundamental Physics of the Universe, via Beirut 2, 34151 Trieste, Italy
⁸ INFN – Sezione di Trieste, 34100 Trieste, Italy
⁹ Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians-Universität München, Scheinerstr.1, 81679 München, Germany
¹⁰ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Straße 1, 85741 Garching, Germany
¹¹ Aix-Marseille Univ, CNRS, CNES, LAM, Marseille, France

Received: 26 April 2022
Accepted: 11 August 2022

Abstract

We demonstrate how to use persistent homology for cosmological parameter inference in a tomographic cosmic shear survey. We obtain the first cosmological parameter constraints from persistent homology by applying our method to the first-year data of the Dark Energy Survey. To obtain these constraints, we analyse the topological structure of the matter distribution by extracting persistence diagrams from signal-to-noise maps of aperture masses. This presents a natural extension to the widely used peak count statistics. Extracting the persistence diagrams from the cosmo-SLICS, a suite of N-body simulations with variable cosmological parameters, we interpolate the signal using Gaussian processes and marginalise over the most relevant systematic effects, including intrinsic alignments and baryonic effects. For the structure growth parameter, we find S₈ = 0.747_−0.031^+0.025, which is in full agreement with other late-time probes. We also constrain the intrinsic alignment parameter to A = 1.54 ± 0.52, which constitutes a detection of the intrinsic alignment effect at almost 3σ.