We use the joint measurement of geometry and growth from anisotropic galaxy clustering in the Baryon Oscillation Spectroscopic Survey ( BOSS ) Data Release 9 ( DR9 ) CMASS sample reported by Reid et al . to constrain dark energy ( DE ) properties and possible deviations from the General Relativity ( GR ) .
Assuming GR and taking a prior on the linear matter power spectrum at high redshift from the cosmic microwave background ( CMB ) , anisotropic clustering of the CMASS DR9 galaxies alone constrains \Omega _ { m } = 0.308 \pm 0.022 and 100 \Omega _ { k } = 5.9 \pm 4.8 for w = -1 , or w = -0.91 \pm 0.12 for \Omega _ { k } = 0 .
When combined with the full CMB likelihood , the addition of the anisotropic clustering measurements to the spherically-averaged BAO location increases the constraining power on dark energy by a factor of 4 in a flat CDM cosmology with constant dark energy equation of state w ( giving w = -0.87 \pm 0.05 ) .
This impressive gain depends on our measurement of both the growth of structure and Alcock-Paczynski effect , and is not realised when marginalising over the amplitude of redshift space distortions .
Combining with both the CMB and Supernovae Type Ia ( SNeIa ) , we find \Omega _ { m } = 0.281 \pm 0.014 and 1000 \Omega _ { k } = -9.2 \pm 5.0 for w = -1 , or w _ { 0 } = -1.13 \pm 0.12 and w _ { a } = 0.65 \pm 0.36 assuming \Omega _ { k } = 0 .
Finally , when a \Lambda CDM background expansion is assumed , the combination of our estimate of the growth rate with previous growth measurements provides tight constraints on the parameters describing possible deviations from GR giving \gamma = 0.64 \pm 0.05 .
For one parameter extensions of the flat \Lambda CDM model , we find a \sim 2 \sigma preference either for w > -1 or slower growth than in GR .
However , the data is fully consistent with the concordance model , and the evidence for these additional parameters is weaker than 2 \sigma .