Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years
  of Observations Including First Results from APOGEE-South   The spectral analysis and data products in Data Release 16 (DR16; December
2019) from the high-resolution near-infrared APOGEE-2/SDSS-IV survey are
described. Compared to the previous APOGEE data release (DR14; July 2017),
APOGEE DR16 includes about 200000 new stellar spectra, of which 100000 are from
a new southern APOGEE instrument mounted on the 2.5 m du Pont telescope at Las
Campanas Observatory in Chile. DR16 includes all data taken up to August 2018,
including data released in previous data releases. All of the data have been
re-reduced and re-analyzed using the latest pipelines, resulting in a total of
473307 spectra of 437445 stars. Changes to the analysis methods for this
release include, but are not limited to, the use of MARCS model atmospheres for
calculation of the entire main grid of synthetic spectra used in the analysis,
a new method for filling "holes" in the grids due to unconverged model
atmospheres, and a new scheme for continuum normalization. Abundances of the
neutron capture element Ce are included for the first time. A new scheme for
estimating uncertainties of the derived quantities using stars with multiple
observations has been applied, and calibrated values of surface gravities for
dwarf stars are now supplied. Compared to DR14, the radial velocities derived
for this release more closely match those in the Gaia DR2 data base, and a
clear improvement in the spectral analysis of the coolest giants can be seen.
The reduced spectra as well as the result of the analysis can be downloaded
using links provided in the SDSS DR16 web page.

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The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: gr-qc
3
The categories of this paper are: physics
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The categories of this paper are: q-alg
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The categories of this paper are: atom-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: math