The Baryon Oscillation Spectroscopic Survey of SDSS-III

TL;DR

The Baryon Oscillation Spectroscopic Survey (BOSS) aims to map large-scale structure through galaxy and quasar observations, providing precise measurements of cosmic distances and expansion rates to improve understanding of dark energy.

Contribution

This paper presents the design, target selection, data analysis, and early results of BOSS, a large spectroscopic survey that extends previous efforts to measure baryon acoustic oscillations.

Findings

First detection of large-scale three-dimensional clustering of the Lyman alpha forest.

Strong detection of BAO in massive galaxy clustering at z=0.57.

Projected high-precision measurements of cosmic distances and expansion rates.

Abstract

The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large scale structure. BOSS uses 1.5 million luminous galaxies as faint as i=19.9 over 10,000 square degrees to measure BAO to redshifts z<0.7. Observations of neutral hydrogen in the Lyman alpha forest in more than 150,000 quasar spectra (g<22) will constrain BAO over the redshift range 2.15<z<3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Lyman alpha forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance D_A to an accuracy of 1.0% at redshifts z=0.3 and z=0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Lyman alpha forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D_A(z) and H^{-1}(z) parameters to an accuracy of 1.9% at z~2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS.