The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey:
  Final Data from SDSS-III
  The third generation of the Sloan Digital Sky Survey (SDSS-III) took data
from 2008 to 2014 using the original SDSS wide-field imager, the original and
an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared
high-resolution spectrograph, and a novel optical interferometer. All the data
from SDSS-III are now made public. In particular, this paper describes Data
Release 11 (DR11) including all data acquired through 2013 July, and Data
Release 12 (DR12) adding data acquired through 2014 July (including all data
included in previous data releases), marking the end of SDSS-III observing.
Relative to our previous public release (DR10), DR12 adds one million new
spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic
Survey (BOSS) over an additional 3000 sq. deg of sky, more than triples the
number of H-band spectra of stars as part of the Apache Point Observatory (APO)
Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial
velocity measurements of 5500 stars from the Multi-Object APO Radial Velocity
Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include measured
abundances of 15 different elements for each star. In total, SDSS-III added
2350 sq. deg of ugriz imaging; 155,520 spectra of 138,099 stars as part of the
Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey;
2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216
stars over 9376 sq. deg; 618,080 APOGEE spectra of 156,593 stars; and 197,040
MARVELS spectra of 5,513 stars. Since its first light in 1998, SDSS has imaged
over 1/3 of the Celestial sphere in five bands and obtained over five million
astronomical spectra.
