SDSS-III: MASSIVE SPECTROSCOPIC SURVEYS OF THE DISTANT UNIVERSE, THE MILKY WAY, AND EXTRA-SOLAR PLANETARY SYSTEMS

Abstract

Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II),\nSDSS-III is a program of four spectroscopic surveys on three scientific themes:\ndark energy and cosmological parameters, the history and structure of the Milky\nWay, and the population of giant planets around other stars. In keeping with\nSDSS tradition, SDSS-III will provide regular public releases of all its data,\nbeginning with SDSS DR8 (which occurred in Jan 2011). This paper presents an\noverview of the four SDSS-III surveys. BOSS will measure redshifts of 1.5\nmillion massive galaxies and Lya forest spectra of 150,000 quasars, using the\nBAO feature of large scale structure to obtain percent-level determinations of\nthe distance scale and Hubble expansion rate at z<0.7 and at z~2.5. SEGUE-2,\nwhich is now completed, measured medium-resolution (R=1800) optical spectra of\n118,000 stars in a variety of target categories, probing chemical evolution,\nstellar kinematics and substructure, and the mass profile of the dark matter\nhalo from the solar neighborhood to distances of 100 kpc. APOGEE will obtain\nhigh-resolution (R~30,000), high signal-to-noise (S/N>100 per resolution\nelement), H-band (1.51-1.70 micron) spectra of 10^5 evolved, late-type stars,\nmeasuring separate abundances for ~15 elements per star and creating the first\nhigh-precision spectroscopic survey of all Galactic stellar populations (bulge,\nbar, disks, halo) with a uniform set of stellar tracers and spectral\ndiagnostics. MARVELS will monitor radial velocities of more than 8000 FGK stars\nwith the sensitivity and cadence (10-40 m/s, ~24 visits per star) needed to\ndetect giant planets with periods up to two years, providing an unprecedented\ndata set for understanding the formation and dynamical evolution of giant\nplanet systems. (Abridged)\n