Constraints on the dark energy dipole from large-scale structures

Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza de San Juan, 1, planta 2, 44001 Teruel, Spain
e-mail: ghurier@cefca.es

Received: 6 September 2016
Accepted: 28 October 2016

Abstract

The high-significance measurement of large-scale structure signals enables testing the isotropy of the Universe. The measurement of cosmological parameters through the large-scale distribution of matter is now a mature domain. This approach is mainly limited by our knowledge of astrophysical processes that are used to observe the large-scale structure. However, when we assume that these astrophysical processes are the same across the Universe, then it is possible to tightly constrain the isotropy of cosmological parameters across the sky. Particularly the X-SZ cross-correlation has been shown to be a probe of the large scale structures that has a high signal-to-noise ratio and low bias. For this analysis, we used a localized measurement of the X-SZ cross-correlation as a test of the cosmological parameter isotropy. Using the scatter of the X-SZ cross-correlation across the sky, we derive cosmological constraints σ₈(Ω_m/ 0.28)^0.34 = 0.78 ± 0.02 and tight isotropy constraints on the dark energy dipole ΔΩ_Λ < 0.07 at 95% confidence level.