The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Measuring D_A and H at z=0.57 from the Baryon Acoustic Peak in the Data Release 9 Spectroscopic Galaxy Sample

TL;DR

This paper measures the angular diameter distance and Hubble parameter at redshift 0.57 using baryon acoustic oscillations in galaxy data from SDSS-III BOSS, confirming consistency with the standard cosmological model.

Contribution

It provides new, precise measurements of D_A and H at z=0.57 using two robust methods, improving constraints on cosmological parameters.

Findings

D_A(0.57) = 1408 +/- 45 Mpc

H(0.57) = 92.9 +/- 7.8 km/s/Mpc

Results align with standard cosmological model

Abstract

We present measurements of the angular diameter distance to and Hubble parameter at z=0.57 from the measurement of the baryon acoustic peak in the correlation of galaxies from the Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey. Our analysis is based on a sample from Data Release 9 of 264,283 galaxies over 3275 square degrees in the redshift range 0.43<z<0.70. We use two different methods to provide robust measurement of the acoustic peak position across and along the line of sight in order to measure the cosmological distance scale. We find D_A(0.57) = 1408 +/- 45 Mpc and H(0.57) = 92.9 +/- 7.8 km/s/Mpc for our fiducial value of the sound horizon. These results from the anisotropic fitting are fully consistent with the analysis of the spherically averaged acoustic peak position presented in Anderson et al, 2012. Our distance measurements are a close match to the predictions of the standard cosmological model featuring a cosmological constant and zero spatial curvature.