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[34.02] The Sloan Digital Sky Survey: First Results

J.E. Gunn (Princeton U.)

The Sloan Digital Sky Survey is nearing the end of the commissioning phases of both its imaging and spectroscopic modes. The goal of the SDSS is to produce a digital photometric survey of the roughly 10,000 square degrees of the Northern Galactic Cap in five bands to a limiting (5\sigma, point source) sensitivity of about 23^m in its more sensitive bands, and a spectroscopic survey (4000 - 9000 Å{}) of 10⁵ quasars and 10⁶ galaxies, selected from the imaging data according to precisely defined criteria. The SDSS expects to provide accurate photometric measurements (between 2-5% at 20^m) of about 5\times 10⁷ galaxies and a somewhat larger number of stars. The major goal of the SDSS is the detailed mapping of a volume of the nearby Universe (to about z = 0.2) many times larger than the largest structures predicted by current theories of structure formation. The quasar survey allows the measurement of structure to the horizon scale and, via the absorption line systems, of the evolution of that structure over the age of the Universe. Part of the galaxy survey provides an essentially distance limited sample of brightest red galaxies to about z = 0.5, tracing the structure of the highest density regions of the nearby Universe. The SDSS data also provide large samples for investigating subjects ranging from asteroids to high redshift quasars. Results obtained from the test data include the observation of a large sample of high redshift (z>4.5) quasars, of the first field methane dwarf and of galaxy-galaxy lensing.