UC Berkeley

BOSS, the Baryon Oscillation Spectroscopic Survey, is a 5-year program to measure the absolute cosmic distance scale and expansion rate with percent-level precision at redshifts z<0.7 and z~2.5. BOSS uses the "standard ruler" provided by baryon acoustic oscillations (BAO). BOSS will achieve a near optimal measurement of the BAO scale at z<0.7, with a redshift survey of 1.5 million luminous galaxies. It will pioneer a new method of BAO measurement at high redshift, using the LyA forest to 160,000 QSOs in the redshift range 2.1