Abundances, Stellar Parameters, and Spectra From the SDSS-III/APOGEE
  Survey
  The SDSS-III/APOGEE survey operated from 2011-2014 using the APOGEE
spectrograph, which collects high-resolution (R~22,500), near-IR (1.51-1.70
microns) spectra with a multiplexing (300 fiber-fed objects) capability. We
describe the survey data products that are publicly available, which include
catalogs with radial velocity, stellar parameters, and 15 elemental abundances
for over 150,000 stars, as well as the more than 500,000 spectra from which
these quantities are derived. Calibration relations for the stellar parameters
(Teff, log g, [M/H], [alpha/M]) and abundances (C, N, O, Na, Mg, Al, Si, S, K,
Ca, Ti, V, Mn, Fe, Ni) are presented and discussed. The internal scatter of the
abundances within clusters indicates that abundance precision is generally
between 0.05 and 0.09 dex across a broad temperature range; within more limited
ranges and at high S/N, it is smaller for some elemental abundances. We assess
the accuracy of the abundances using comparison of mean cluster metallicities
with literature values, APOGEE observations of the solar spectrum and of
Arcturus, comparison of individual star abundances with other measurements, and
consideration of the locus of derived parameters and abundances of the entire
sample, and find that it is challenging to determine the absolute abundance
scale; external accuracy may be good to 0.1-0.2 dex. Uncertainties may be
larger at cooler temperatures (Teff<4000K). Access to the public data release
and data products is described, and some guidance for using the data products
is provided.
