Weak lensing and dark energy: the impact of dark energy on nonlinear dark matter clustering

TL;DR

This paper demonstrates that precise modeling of nonlinear matter power spectrum corrections due to dark energy is crucial for accurate dark energy parameter constraints from future weak lensing surveys, significantly reducing biases and improving measurement precision.

Contribution

It quantifies the impact of dark energy modifications on nonlinear matter power spectrum modeling and highlights the necessity for percent-level accuracy in future weak lensing analyses.

Findings

Poor approximation causes > 1 sigma bias in dark energy parameters.

Accurate nonlinear corrections improve dark energy constraints by a factor of two.

Future surveys can measure the dark energy equation of state to 5-10% accuracy.

Abstract

We examine the influence of percent-level dark energy corrections to the nonlinear matter power spectrum on constraints of the dark energy equation of state from future weak lensing probes. We explicitly show that a poor approximation (off by > 10%) to the nonlinear corrections causes a > 1 sigma bias on the determination of the dark energy equation of state. Future weak lensing surveys must therefore incorporate dark energy modifications to the nonlinear matter power spectrum accurate to the percent-level, to avoid introducing significant bias in their measurements. For the WMAP5 cosmology, the more accurate power spectrum is more sensitive to dark energy properties, resulting in a factor of two improvement in dark energy equation of state constraints. We explore the complementary constraints on dark energy from future weak lensing and supernova surveys. A space-based, JDEM-like survey measures the equation of state in five independent redshift bins to ~10%, while this improves to ~5% for a wide-field ground-based survey like LSST. These constraints are contingent upon our ability to control weak lensing systematic uncertainties to the sub-percent level.