Abstract:

We use the observed anisotropic clustering of galaxies in the BaryonOscillation Spectroscopic Survey Data Release 11 CMASS sample to measurethe linear growth rate of structure, the Hubble expansion rate and thecomoving distance scale. Our sample covers 8498 ${\rm deg}^2$ andencloses an effective volume of 6.0 ${\rm Gpc}^3$ at an effectiveredshift of $\bar{z} = 0.57$. We find $f\sigma_8 = 0.441 \pm 0.044$, $H= 93.1 \pm 3.0\ {\mathrm{km}\ \mathrm{s}^{-1} \mathrm{Mpc}^{-1}}$ and$D_{\rm A} = 1380 \pm 23\ {\rm Mpc}$ when fitting the growth andexpansion rate simultaneously. When we fix the background expansion tothe one predicted by spatially-flat $\Lambda$CDM model in agreement withrecent Planck results, we find $f\sigma_8 = 0.447 \pm 0.028$ (6 per centaccuracy). While our measurements are generally consistent with thepredictions of $\Lambda$CDM and General Relativity, they mildly favormodels in which the strength of gravitational interactions is weakerthan what is predicted by General Relativity. Combining our measurementswith recent cosmic microwave background data results in tightconstraints on basic cosmological parameters and deviations from thestandard cosmological model. Separately varying these parameters, wefind $w = -0.983 \pm 0.075$ (8 per cent accuracy) and $\gamma = 0.69 \pm0.11$ (16 per cent accuracy) for the effective equation of state of darkenergy and the growth rate index, respectively. Both constraints are ingood agreement with the standard model values of $w=-1$ and $\gamma =0.554$.

Notes:

16 pages, 18 figures, submitted to MNRAS

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