We analyze the clustering of large scale structure in the Universe in a model independent method , accounting for anisotropic effects along and transverse to the line of sight .
The Baryon Oscillation Spectroscopy Survey Data Release 11 provides a large sample of 690,000 galaxies , allowing determination of the Hubble expansion H , angular distance D _ { A } , and growth rate G _ { \Theta } at an effective redshift of z = 0.57 .
After careful bias and convergence studies of the effects from small scale clustering , we find that cutting transverse separations below 40 Mpc/ h delivers robust results while smaller scale data leads to a bias due to unmodelled nonlinear and velocity effects .
The converged results are in agreement with concordance \Lambda CDM cosmology , general relativity , and minimal neutrino mass , all within the 68 % confidence level .
We also present results separately for the northern and southern hemisphere sky , finding a slight tension in the growth rate – potentially a signature of anisotropic stress , or just covariance with small scale velocities – but within 68 % CL .