Sloan Digital Sky Survey: Completion of Survey Observations and Studies for Cosmology

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The SDSS project finished its originally planned operations in June 2005. We began the construction of the instruments in 1993 and the operation in 2000. During the time it attained imaging for 115% of the planned region and spectroscopy for 76%. Somewhat lower achievement of the spectroscopy is due to poor weather in the winter and spring of 2004 and 2005. We began a new programme, SDSS-II for another three years from July 2005, for the purpose primarily to fill the missing observed regions, supplemented with two new projects, for which SDSS turns out to be extremely useful from our experience.To date we have made public the imaging data for 6670 square degrees that comprises 180 million astronomical objects, a half of them being galaxies, and spectra of 850 thousand galaxies. The present Grant-in-Aid project corresponds to the mid to the latest part of the original project and SDSS-II.Analyses of the acquired data were made from time to time, and our achievements have already satisfied well the scientific goals set in the beginning of the project. The data we acquired are and will be used world-widely throughout this century for precision astronomical sciences. The SDSS project is regarded as the most successful scientific project in our time. The members of the Grant-in-Aid authored 108 papers that have already received over 16000 citations in the community.The science produced ranges from cosmology, large-scale structure of the universe, high redshift quasars and studies for high redshift universe, galactic astronomy, stellar science, especially that of low temperature stars, and asteroid science. Probably the most important is the quantitative verification that our universe and its evolution are described well by the model of the universe dominated by cold dark matter and dark energy. This allowed our basic understanding of the Universe. The result also indicates the direction and objectives to be studied with large-scale astronomical projects in the future.