Probing Dark Energy Anisotropy

TL;DR

This paper investigates the potential anisotropy of dark energy using cosmological surveys and simulations, assessing observational sensitivities and systematic effects in a Bianchi I universe model.

Contribution

It introduces a method to constrain dark energy anisotropy through simulated distance measurements and compares sensitivities of different observational probes.

Findings

Cosmic microwave background strongly limits anisotropic effects.

Simulated measurements provide bounds on anisotropy in Bianchi I models.

Fitting for line of sight properties can misestimate anisotropic signals.

Abstract

Wide area cosmological surveys enable investigation of whether dark energy properties are the same in different directions on the sky. Cosmic microwave background observations strongly restrict any dynamical effects from anisotropy, in an integrated sense. For more local constraints we compute limits from simulated distance measurements for various distributions of survey fields in a Bianchi I anisotropic universe. We then consider the effects of fitting for line of sight properties where isotropic dynamics is assumed (testing the accuracy through simulations) and compare sensitivities of observational probes for anisotropies, from astrophysical systematics as well as dark energy. We also point out some interesting features of anisotropic expansion in Bianchi I cosmology.