The WiggleZ Dark Energy Survey: constraining galaxy bias and cosmic growth with three-point correlation functions

Higher order statistics are a useful and complementary tool for measuring the clustering of galaxies, containing information on the non-Gaussian evolution and morphology of large-scale structure in the Universe. In this work we present measurements of the three-point correlation function (3PCF) for 187 000 galaxies in the WiggleZ spectroscopic galaxy survey. We explore the WiggleZ 3PCF scale and shape dependence at three different epochs z = 0.35, 0.55 and 0.68, the highest redshifts where these measurements have been made to date. Using N-body simulations to predict the clustering of dark matter, we constrain the linear and non-linear bias parameters of WiggleZ galaxies with respect to dark matter, and marginalize over them to obtain constraints on σ8(z), the variance of perturbations on a scale of 8 h^−1 Mpc and its evolution with redshift. These measurements of σ_8(z), which have 10–20 per cent accuracies, are consistent with the predictions of the Λ cold dark matter concordance cosmology and test this model in a new way.