Gravitational Lensing Simulations I : Covariance Matrices and Halo Catalogues

TL;DR

This paper introduces the TCS simulation suite for gravitational lensing, providing detailed covariance matrices and halo catalogues to improve the interpretation of small-scale lensing signals in large surveys.

Contribution

It presents a comprehensive simulation suite that incorporates all known lensing corrections, enabling more accurate modeling of non-linear and secondary effects in lensing analyses.

Findings

Simulations resolve signals at sub-arcminute scales (~10^4 in multipole space)

Computed non-Gaussian covariance matrices for key lensing estimators

Generated halo catalogues with properties for galaxy population modeling

Abstract

Gravitational lensing surveys have now become large and precise enough that the interpretation of the lensing signal has to take into account an increasing number of theoretical limitations and observational biases. Since the lensing signal is the strongest at small angular scales, only numerical simulations can reproduce faithfully the non-linear dynamics and secondary effects at play. This work is the first of a series in which all gravitational lensing corrections known so far will be implemented in the same set of simulations, using realistic mock catalogues and non-Gaussian statistics. In this first paper, we present the TCS simulation suite and compute basic statistics such as the second and third order convergence and shear correlation functions. These simple tests set the range of validity of our simulations, which are resolving most of the signals at the sub-arc minute level (or $\ell \sim 10^4$). We also compute the non-Gaussian covariance matrix of several statistical estimators, including many that are used in the Canada France Hawaii Telescope Lensing Survey (CFHTLenS). From the same realizations, we construct halo catalogues, computing a series of properties that are required by most galaxy population algorithms. These simulation products are publicly available for download.