The WiggleZ Dark Energy Survey: mapping the distance-redshift relation with baryon acoustic oscillations

TL;DR

This paper reports measurements of baryon acoustic oscillations at multiple redshifts using the WiggleZ survey, combining data with other surveys to constrain dark energy properties and cosmological parameters.

Contribution

It provides new BAO measurements at higher redshifts and combines them with other datasets to improve constraints on dark energy and cosmological parameters.

Findings

BAO detected at 4.9-sigma significance

Consistent dark energy equation-of-state w ≈ -1

Spatial curvature Omega_k ≈ 0

Abstract

We present measurements of the baryon acoustic peak at redshifts z = 0.44, 0.6 and 0.73 in the galaxy correlation function of the final dataset of the WiggleZ Dark Energy Survey. We combine our correlation function with lower-redshift measurements from the 6-degree Field Galaxy Survey and Sloan Digital Sky Survey, producing a stacked survey correlation function in which the statistical significance of the detection of the baryon acoustic peak is 4.9-sigma relative to a zero-baryon model with no peak. We fit cosmological models to this combined baryon acoustic oscillation (BAO) dataset comprising six distance-redshift data points, and compare the results to similar fits to the latest compilation of supernovae (SNe) and Cosmic Microwave Background (CMB) data. The BAO and SNe datasets produce consistent measurements of the equation-of-state w of dark energy, when separately combined with the CMB, providing a powerful check for systematic errors in either of these distance probes. Combining all datasets we determine w = -1.03 +/- 0.08 for a flat Universe, consistent with a cosmological constant model. Assuming dark energy is a cosmological constant and varying the spatial curvature, we find Omega_k = -0.004 +/- 0.006.