The Second Data Release of the Sloan Digital Sky Survey

Abstract

The Sloan Digital Sky Survey (SDSS) has validated and made publicly available its Second Data Release. This data release consists of 3324 deg² of five-band (ugriz) imaging data with photometry for over 88 million unique objects, 367,360 spectra of galaxies, quasars, stars, and calibrating blank sky patches selected over 2627 deg² of this area, and tables of measured parameters from these data. The imaging data reach a depth of r ≈ 22.2 (95% completeness limit for point sources) and are photometrically and astrometrically calibrated to 2% rms and 100 mas rms per coordinate, respectively. The imaging data have all been processed through a new version of the SDSS imaging pipeline, in which the most important improvement since the last data release is fixing an error in the model fits to each object. The result is that model magnitudes are now a good proxy for point-spread function magnitudes for point sources, and Petrosian magnitudes for extended sources. The spectroscopy extends from 3800 to 9200 Å at a resolution of 2000. The spectroscopic software now repairs a systematic error in the radial velocities of certain types of stars and has substantially improved spectrophotometry. All data included in the SDSS Early Data Release and First Data Release are reprocessed with the improved pipelines and included in the Second Data Release. Further characteristics of the data are described, as are the data products themselves and the tools for accessing them.

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Affiliated Institutions

• Japan Women's University JP
• Los Alamos National Laboratory US
• Lawrence Berkeley National Laboratory US
• Space Telescope Science Institute US
• United States Naval Research Laboratory US
• United States Naval Observatory US
• Carnegie Mellon University US
• Rensselaer Polytechnic Institute US
• Fermi National Accelerator Laboratory US
• University of Pennsylvania US
• University of Colorado Boulder US
• University of Edinburgh GB
• Laboratory for Atmospheric and Space Physics US
• University of Illinois Urbana-Champaign US
• University of Chicago US
• University of Pittsburgh US
• Eötvös Loránd University HU
• Nagoya University JP
• New Mexico State University US
• Princeton University US
• University of Michigan US
• Institut d'Estudis Espacials de Catalunya ES
• European Organization for Nuclear Research CH
• Royal Observatory GB
• New York University US
• Microsoft (United States) US
• Tokyo University of Science JP
• University of Washington US
• Johns Hopkins University US
• University of Sussex GB
• The University of Tokyo JP
• Tohoku University JP
• National Astronomical Observatory of Japan JP
• Université Bourgogne Franche-Comté FR
• Max Planck Institute for Astronomy DE

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