APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South

Journal Article · Tue Sep 01 04:00:00 EDT 2020 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/ABA592· OSTI ID:23013335

Jönsson, Henrik ^[1]; Holtzman, Jon A. ^[2]; Prieto, Carlos Allende; García-Hernández, D. A.; Masseron, Thomas; Osorio, Yeisson ^[3]; Cunha, Katia ^[4]; Hasselquist, Sten ^[5]; Shetrone, Matthew ^[6]; Smith, Verne ^[7]; Stringfellow, Guy S. ^[8]; Bizyaev, Dmitry ^[9]; Edvardsson, Bengt ^[10]; Majewski, Steven R. ^[11]; Mészáros, Szabolcs ^[12]; others, and

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1. Materials Science and Applied Mathematics, Malmö University, SE-205 06 Malmö (Sweden)
2. New Mexico State University, Las Cruces, NM 88003 (United States)
3. Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain)
4. Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States)
5. Department of Physics & Astronomy, University of Utah, Salt Lake City, UT, 84112 (United States)
6. University of Texas at Austin, McDonald Observatory, Fort Davis, TX 79734 (United States)
7. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
8. Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO, 80309-0389 (United States)
9. Apache Point Observatory and New Mexico State University, PO Box 59, sunspot, NM 88349-0059 (United States)
10. Theoretical Astrophysics, Division of Astronomy & Space Physics, Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala (Sweden)
11. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States)
12. ELTE Eötvös Loránd University, Gothard Astrophysical Observatory, 9700 Szombathely, Szent Imre h. st. 112 (Hungary)

The spectral analysis and data products in Data Release 16 (DR16; 2019 December) from the high-resolution near-infrared Apache Point Observatory Galactic Evolution Experiment (APOGEE)-2/Sloan Digital Sky Survey (SDSS)-IV survey are described. Compared to the previous APOGEE data release (DR14; 2017 July), APOGEE DR16 includes about 200,000 new stellar spectra, of which 100,000 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 2018 August, 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 473,307 spectra of 437,445 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 database, 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 on the SDSS DR16 web page.

• OSTI ID: 23013335
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 3 Vol. 160; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPARATIVE EVALUATIONS
DWARF STARS
GALACTIC EVOLUTION
RADIAL VELOCITY
SPECTRA
STELLAR ATMOSPHERES