Model-independent measurements of cosmic expansion and growth at z = 0.57 using the anisotropic clustering of CMASS galaxies from the Sloan Digital Sky Survey Data Release 9

October 2014 • 2014MNRAS.443.2950W

Authors • Wang, Yun

Abstract • We analyse the anisotropic two-dimensional galaxy correlation function (2DCF) of the CMASS galaxy samples from the Sloan Digital Sky Survey Data Release 9 of the Baryon Oscillation Spectroscopic Survey data. Modelling the 2DCF fully including non-linear effects and redshift space distortions (RSD) in the scale range of 30-120 h-1 Mpc, we find H(0.57)rs(zd)/c = 0.0444 ± 0.0019, DA(0.57)/rs(zd) = 9.01 ± 0.23, and fg(0.57)σ8(0.57) = 0.474 ± 0.075, where rs(zd) is the sound horizon at the drag epoch computed using a simple integral, fg(z) is the growth rate at redshift z, and σ8(z) represents the matter power spectrum normalization on 8 h-1 Mpc scale at z. We find that the scales larger than 120 h-1 Mpc are dominated by noise in the 2DCF analysis, and that the inclusion of scales 30-40 h-1 Mpc significantly tightens the RSD measurement. Our measurements are consistent with previous results using the same data, but have significantly better precision since we are using all the information from the 2DCF in the scale range of 30-120 h-1 Mpc. Our measurements have been marginalized over sufficiently wide priors for the relevant parameters; they can be combined with other data to probe dark energy and gravity.


IPAC Authors


Yun Wang

Senior Scientist