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 Ωm = 0.308 ± 0.022 and 100Ωk = 5.9 ± 4.8 for w = −1, or w = −0.91 ± 0.12 for Ωk = 0. When combined with the full CMB likelihood, the addition of the anisotropic clustering measurements to the spherically averaged baryon acoustic oscillation location increases the constraining power on DE by a factor of 4 in a flat cold dark matter (CDM) cosmology with constant DE equation of state w (giving w = −0.87 ± 0.05). This impressive gain depends on our measurement of both the growth of structure and the Alcock–Paczynski effect, and is not realized when marginalizing over the amplitude of redshift-space distortions. Combining with both the CMB and Type Ia supernovae, we find Ωm = 0.281 ± 0.014 and 1000Ωk = −9.2 ± 5.0 for w = −1, or w0 = −1.13 ± 0.12 and wa = 0.65 ± 0.36 assuming Ωk = 0. Finally, when a ΛCDM 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 γ = 0.64 ± 0.05. For one-parameter extensions of the flat ΛCDM model, we find a ∼2σ preference either for w > −1 or slower growth than in GR. However, the data are fully consistent with the concordance model, and evidence for these additional parameters is weaker than 2σ.
- cosmological parameters
- dark energy
- dark matter
- distance scale
- large-scale structure of Universe