THE DATA REDUCTION PIPELINE FOR THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT

• Published in: The Astronomical journal 2015-12, Vol.150 (6), p.1-23
• Main Authors: Nidever, David L., Holtzman, Jon A., Prieto, Carlos Allende, Beland, Stephane, Bender, Chad, Bizyaev, Dmitry, Burton, Adam, Desphande, Rohit, Fleming, Scott W., García Pérez, Ana E., Hearty, Fred R., Majewski, Steven R., Mészáros, Szabolcs, Muna, Demitri, Nguyen, Duy, Schiavon, Ricardo P., Shetrone, Matthew, Skrutskie, Michael F., Sobeck, Jennifer S., Wilson, John C.
• Format: Article
• Language: English
• Subjects: ABSORPTION SPECTROSCOPY; Apogees; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; Atmospherics; CORRECTIONS; DATA ANALYSIS; Data reduction; ELEMENT ABUNDANCE; EMISSION SPECTROSCOPY; Galactic bulge; GALACTIC EVOLUTION; galaxies: abundances; galaxies: halos; galaxies: kinematics and dynamics; IMAGE PROCESSING; Local Group; methods: data analysis; MILKY WAY; NEAR INFRARED RADIATION; OPTICAL FIBERS; RED GIANT STARS; RESOLUTION; SIGNAL-TO-NOISE RATIO; Spectra; techniques: image processing; TELESCOPES; Three dimensional
• ISSN: 0004-6256; 1538-3881; 1538-3881
• DOI: 10.1088/0004-6256/150/6/173

ABSTRACT The Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, explores the stellar populations of the Milky Way using the Sloan 2.5-m telescope linked to a high resolution (R ∼ 22,500), near-infrared (1.51-1.70 m) spectrograph with 300 optical fibers. For over 150,000 predominantly red giant branch stars that APOGEE targeted across the Galactic bulge, disks and halo, the collected high signal-to-noise ratio (>100 per half-resolution element) spectra provide accurate (∼0.1 km s−1) RVs, stellar atmospheric parameters, and precise ( 0.1 dex) chemical abundances for about 15 chemical species. Here we describe the basic APOGEE data reduction software that reduces multiple 3D raw data cubes into calibrated, well-sampled, combined 1D spectra, as implemented for the SDSS-III/APOGEE data releases (DR10, DR11 and DR12). The processing of the near-IR spectral data of APOGEE presents some challenges for reduction, including automated sky subtraction and telluric correction over a 3°-diameter field and the combination of spectrally dithered spectra. We also discuss areas for future improvement.