Date Published:

October 1, 2016

Abstract:

With the largest spectroscopic galaxy survey volume drawn from theSDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), we can extractcosmological constraints from the measurements of redshift and geometricdistortions at quasi-linear scales (e.g. above 50 h^-1 Mpc).We analyse the broad-range shape of the monopole and quadrupolecorrelation functions of the BOSS Data Release 12 (DR12) CMASS galaxysample, at the effective redshift z = 0.59, to obtain constraints on theHubble expansion rate H(z), the angular- diameter distanceD_A(z), the normalized growth rate f(z)σ₈(z),and the physical matter density Ω_m h². Weobtain robust measurements by including a polynomial as the model forthe systematic errors, and find it works very well against thesystematic effects, e.g. ones induced by stars and seeing. We provideaccurate measurements{D_A(0.59)r_s,fid/r_s,H(0.59)r_s/r_s,fid,f(0.59)σ₈(0.59), Ω_m h²} ={1427 ± 26 Mpc, 97.3 ± 3.3 km s^-1Mpc^-1, 0.488 ± 0.060, 0.135 ± 0.016}, wherer_s is the comoving sound horizon at the drag epoch andr_s,fid = 147.66 Mpc is the sound scale of the fiducialcosmology used in this study. The parameters which are not wellconstrained by our galaxy clustering analysis are marginalized over withwide flat priors. Since no priors from other data sets, e.g. cosmicmicrowave background (CMB), are adopted and no dark energy models areassumed, our results from BOSS CMASS galaxy clustering alone may becombined with other data sets, i.e. CMB, SNe, lensing or other galaxyclustering data to constrain the parameters of a given cosmologicalmodel. The uncertainty on the dark energy equation of state parameter,w, from CMB+CMASS is about 8 per cent. The uncertainty on the curvaturefraction, Ω_k, is 0.3 per cent. We do not find deviationfrom flat ΛCDM.

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