Sloan Digital Sky Survey Data Release 12

Sloan Digital Sky Survey Data Release 12 Sloan Digital Sky Survey Data Release 12 was the twelfth public release of Sloan Digital Sky Survey survey products, issued in 2015, that consolidated optical imaging and spectroscopic measurements collected by the Apache Point Observatory facilities and coordinated by teams at Princeton University and the University of Washington. The release integrated legacy programs from prior collaborations including SEGUE, BOSS, and APOGEE, and supported research by investigators at institutions such as Harvard University, University of Arizona, Max Planck Society, and Carnegie Institution for Science.

Overview

DR12 presented combined data from multi-year campaigns executed under project leadership at the Fermilab-affiliated management framework and with instrumentation developed in partnership with groups at Lawrence Berkeley National Laboratory and Yale University. The release followed data policies influenced by archival precedents set by the Hubble Space Telescope archives and interoperability efforts by the International Astronomical Union working groups, enabling reuse by science teams at centers like Caltech and University of Cambridge.

Data Contents and Coverage

DR12 included calibrated imaging from the Sloan Foundation Telescope at Apache Point Observatory and spectroscopic catalogs from the Baryon Oscillation Spectroscopic Survey component, providing redshifts, stellar parameters, and elemental abundances for large samples used by researchers at Massachusetts Institute of Technology, Johns Hopkins University, Ohio State University, and Pennsylvania State University. The release covered sky regions overlapping legacy surveys such as the Two Micron All Sky Survey footprint and complementary fields observed by the Galaxy Evolution Explorer and data cross-match efforts with catalogs from the Gaia mission and the Wide-field Infrared Survey Explorer. Products comprised millions of photometric detections, hundreds of thousands of optical spectra, and tens of thousands of high-resolution infrared spectra contributed by the APOGEE instrument team, enabling comparisons with spectral libraries at institutions like University of California, Berkeley and Australian National University.

Instrumentation and Processing

Data were acquired with the 2.5-meter Sloan Foundation Telescope outfitted with imagers and multi-object spectrographs built under contracts with teams including engineers from Yale University and scientists from University of Washington. The BOSS spectrograph upgrades increased wavelength coverage and resolution relative to earlier SDSS spectrographs used in collaborations with the Max Planck Institute for Astrophysics, while the APOGEE instrument delivered high-resolution near-infrared spectra developed at laboratories such as Lawrence Livermore National Laboratory. Raw exposures were reduced through pipelines influenced by software from projects at CERN and data models compatible with services run by the National Optical-Infrared Astronomy Research Laboratory; calibration strategies referenced standard stars cataloged by teams at University of Chicago and extinction models from the Infrared Science Archive.

Scientific Highlights and Publications

Analyses based on DR12 supported measurements of the baryon acoustic oscillation scale by consortia including scientists at Kavli Institute for Cosmological Physics and Brookhaven National Laboratory, and informed cosmological parameter constraints in studies involving researchers from Princeton University and University of California, Santa Cruz. Stellar population and chemical evolution studies leveraging DR12 APOGEE data produced results by groups at Rutgers University, University of Virginia, and University of Notre Dame. DR12 underpinned investigations into galaxy formation cited in publications associated with University of Oxford and Max Planck Institute for Astronomy, and contributed to cross-disciplinary work with teams using data from the Keck Observatory and the Very Large Telescope. Major papers and collaboration releases acknowledged contributions from participants affiliated with Space Telescope Science Institute and analyses coordinated with the International Centre for Radio Astronomy Research.

Data Access and Tools

DR12 was distributed via web portals and database services maintained by the Sloan Digital Sky Survey collaboration, with query interfaces modeled after systems developed at Johns Hopkins University and data visualization tools interoperable with software from Astropy Project contributors and utility libraries used by teams at Space Telescope Science Institute. Access methods included structured query language endpoints compatible with the Virtual Observatory protocols promoted by the International Virtual Observatory Alliance and downloadable FITS files used by astronomers at University of Toronto and Max Planck Institute for Extraterrestrial Physics. User support, tutorials, and documentation were provided through outreach coordinated with educators at Smithsonian Institution and archives staff at the National Aeronautics and Space Administration.

Category:Astronomical surveys