Measuring DA and H at z=0.35 from the SDSS DR7 LRGs using baryon acoustic oscillations

Citation:

Xu X, Cuesta AJ, Padmanabhan N, Eisenstein DJ, McBride CK. Measuring DA and H at z=0.35 from the SDSS DR7 LRGs using baryon acoustic oscillations. Monthly Notices of the Royal Astronomical Society. 2013;431 :2834-2860.

Date Published:

May 1, 2013

Abstract:

We present measurements of the angular diameter distanceDA(z) and the Hubble parameter H(z) at z = 0.35 using theanisotropy of the baryon acoustic oscillation (BAO) signal measured inthe galaxy clustering distribution of the Sloan Digital Sky Survey(SDSS) Data Release 7 (DR7) luminous red galaxy (LRG) sample. Our workis the first to apply density-field reconstruction to an anisotropicanalysis of the acoustic peak. Reconstruction partially removes theeffects of non-linear evolution and redshift-space distortions in orderto sharpen the acoustic signal. We present the theoretical frameworkbehind the anisotropic BAO signal and give a detailed account of thefitting model we use to extract this signal from the data. Our methodfocuses only on the acoustic peak anisotropy, rather than the moremodel-dependent anisotropic information from the broad-band power. Wetest the robustness of our analysis methods on 160 Large Suite of DarkMatter Simulation DR7 mock catalogues and find that our models areunbiased at the ˜0.2 per cent level in measuring the BAOanisotropy. After reconstruction we measure DA(z = 0.35) =1050 ± 38 Mpc and H(z = 0.35) = 84.4 ± 7.0 kms-1 Mpc-1 assuming a sound horizon ofrs = 152.76 Mpc. Note that these measurements are correlatedwith a correlation coefficient of 0.57. This represents a factor of 1.4improvement in the error on DA relative to thepre-reconstruction case; a factor of 1.2 improvement is seen for H.

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