The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations in the Data Release 10 and 11 galaxy samples

We present a one per cent measurement of the cosmic distance scale fromthe detections of the baryon acoustic oscillations in the clustering ofgalaxies from the Baryon Oscillation Spectroscopic Survey (BOSS), whichis part of the Sloan Digital Sky Survey III (SDSS-III). Our results comefrom the Data Release 11 (DR11) sample, containing nearly one milliongalaxies and covering approximately 8500 square degrees and the redshiftrange $0.20.7$. We also compare these results with those fromthe publicly released DR9 and DR10 samples. Assuming a concordance$\Lambda$CDM cosmological model, the DR11 sample covers a volume of13Gpc${}^3$ and is the largest region of the Universe ever surveyed atthis density. We measure the correlation function and power spectrum,including density-field reconstruction of the baryon acousticoscillation (BAO) feature. The acoustic features are detected at asignificance of over $7\sigma$ in both the correlation function andpower spectrum. Fitting for the position of the acoustic featuresmeasures the distance relative to the sound horizon at the drag epoch,$r_d$, which has a value of $r_{d,{\rm fid}}=149.28$Mpc in our fiducialcosmology. We find $D_V=(1264\pm25\,{\rm Mpc})(r_d/r_{d,{\rm fid}})$ at$z=0.32$ and $D_V=(2056\pm20\,{\rm Mpc})(r_d/r_{d,{\rm fid}})$ at$z=0.57$. At 1.0 per cent, this latter measure is the most precisedistance constraint ever obtained from a galaxy survey. Separating theclustering along and transverse to the line-of-sight yields measurementsat $z=0.57$ of $D_A=(1421\pm20\,{\rm Mpc})(r_d/r_{d,{\rm fid}})$ and$H=(96.8\pm3.4\,{\rm km/s/Mpc})(r_{d,{\rm fid}}/r_d)$. Our measurementsof the distance scale are in good agreement with previous BAOmeasurements and with the predictions from cosmic microwave backgrounddata for a spatially flat cold dark matter model with a cosmologicalconstant.