2012/06/30 by Lado Samushia, Beth A. Reid, Martin White +19 · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1093/mnras/sts443
published as Monthly Notices of the Royal Astronomical Society, Volume 429, Issue 2, p.1514-1528 (2013) · 16 pages, 13 figures, 5 tables. Matches published version
arxiv created 2012/12/14 · arxiv updated 2015/03/20
We use the joint measurement of geometry and growth from anisotropic galaxy clustering in the Baryon Oscillation Spectroscopic Survey Data Release 9 CMASS sample reported by Reid et al. to constrain dark energy properties and possible deviations from the General Relativity. 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 Ω\rm m = 0.308 ± 0.022 and 100Ω\rm k = 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 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 ± 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 Ω\rm m = 0.281 ± 0.014 and 1000Ω\rm k=-9.2±5.0 for w = -1, or w0 = -1.13 ± 0.12 and w\rm a=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 is fully consistent with the concordance model, and the evidence for these additional parameters is weaker than 2σ.