What’s New in DR14

Data Release 14 (DR14) is the second release of the Sloan Digital Sky Survey IV. DR14 contains new extragalactic optical spectra, new reductions and abundances for stellar infrared spectra, and new datacubes of integral field spectroscopy across the face of nearby galaxies.

Extragalactic spectra

(extended) Baryon Oscillation Spectroscopic Survey (eBOSS)

The SDSS’s component extended Baryon Oscillation Spectroscopic Survey has started its mission in 2014 to map the Universe with the baryon acoustic oscillation (BAO) feature in the large-scale structure of the Universe, using data from both galaxy clustering and the Lyman-α forest.

eBOSS coverage area for DR14 (click to enlarge)

Data Release 14 is the first public data release for eBOSS, and includes optical spectra of Luminous Red Galaxies (LRGs) and quasars (QSOs). The data release also includes optical spectra from a transitional project between BOSS and eBOSS called the Sloan Extended Quasar, ELG, and LRG Survey (SEQUELS), designed to test target selection algorithms for eBOSS. These SEQUELS spectra, as well as previously released BOSS spectra, have been re-reduced using the reduction pipeline updated for DR14.

DR14 also contains the first optical spectra of the eBOSS subprograms SPectroscopic IDentfication of ERosita Sources (SPIDERS) survey and Time-Domain Spectroscopic Survey (TDSS), as well as various Value Added Catalogs, which include, amongst others, targeting information.

eBOSS spectra are available through both the Science Archive Server (SAS) and the Catalog Archive Server (CAS). For more information on the new DR14 eBOSS data, see:

Infrared spectra

Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2)

APOGEE-2 is a large-scale survey of Milky Way stellar chemistry and kinematics. High-resolution infrared (H-band) spectroscopy allows APOGEE-2 to peer through interstellar dust extinction to provide a large, uniform database of precision stellar measurements throughout the Galaxy, spanning the central bulge to the halo.

Number of APOGEE-1+APOGEE-2 stars with spectra in DR14 (click to enlarge.

For DR14, APOGEE-2 is releasing its first spectra, taken during the first two years of SDSS-IV (2014-2016). Along with the spectra, APOGEE-2 is releasing stellar parameters (e.g., $T_{\rm eff}$ and log $g$) and more than 20 elemental abundances derived from those spectra.

DR14 also includes prior APOGEE-1 spectra and data products (from DR10-13) that have been reprocessed with improved data reduction and abundance pipelines, including more accurate telluric absorption corrections. In addition to best-fiting values of global stellar parameters, APOGEE also provides individual elemental abundances and uncertainties, along with parameters and abundances derived with the Cannon pipeline.

APOGEE-2 infrared spectra are available through both the Science Archive Server (SAS) and the Catalog Archive Server (CAS). For more information on the new DR14 APOGEE data, see:

Integral field spectra for nearby galaxies

Mapping Nearby Galaxies at APO (MaNGA)

MaNGA coverage area for DR14 (click to enlarge)

MaNGA is an integral-field spectroscopic survey that will map 10,000 galaxies in the nearby Universe. DR14 is MaNGA’s second public data release, and contains datacubes and row-stacked spectra (RSS) for 2,812 MaNGA galaxies (including ancillary targets and ~50 repeat observations), as well as Value Added Catalogs.

MaNGA observes galaxies with fiber bundles that vary in size from 19 to 127 fibers (12 to 32 arcsec diameter on sky); larger bundles target larger galaxies, resulting in a uniform radial coverage. As a result, the number of spectra within each data cube and RSS file will vary depending on the fiber bundle size.

The MaNGA data cubes and row-stacked spectra are available through both the SAS and the CAS. For more information on the new DR14 MaNGA data, see: