The Limits of Cosmic Shear
Abstract
In this paper we discuss the commonly-used limiting cases, or approximations, for two-point cosmic shear statistics. We discuss the most prominent assumptions in this statistic: the flat-sky (small angle limit), the Limber (Bessel-to-delta function limit) and the Hankel transform (large l-mode limit) approximations; that the vast majority of cosmic shear results to date have used simultaneously. We find that the combined effect of these approximations can suppress power by >1% on scales of l<40. A fully non-approximated cosmic shear study should use a spherical-sky, non-Limber-approximated power spectrum analysis; and a transform involving Wigner small-d matrices in place of the Hankel transform. These effects, unaccounted for, would constitute at least 11% of the total budget for systematic effects for a power spectrum analysis of a Euclid-like experiment; but they are unnecessary.
Cite
@article{arxiv.1611.04954,
title = {The Limits of Cosmic Shear},
author = {Thomas D. Kitching and Justin Alsing and Alan F. Heavens and Raul Jimenez and Jason D. McEwen and Licia Verde},
journal= {arXiv preprint arXiv:1611.04954},
year = {2017}
}
Comments
15 pages, accepted to MNRAS