Browsing by Subject "synoptic survey telescope"
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Item The Milky Way Tomography With SDSS. II. Stellar Metallicity(2008-09) Ivezic, Zeljko; Sesar, Branimir; Juric, Mario; Bond, Nicholas; Dalcanton, Julianne; Rockosi, Constance M.; Yanny, Brian; Newberg, Heidi J.; Beers, Timothy C.; Prieto, Carlos Allende; Wilhelm, Ron; Lee, Young Sun; Sivarani, Thirupathi; Norris, John E.; Bailer-Jones, Coryn A. L.; Fiorentin, Paola Re; Schlegel, David; Uomoto, Alan; Lupton, Robert H.; Knapp, Gillian R.; Gunn, James E.; Covey, Kevin R.; Smith, J. Allyn; Miknaitis, Gajus; Doi, Mamoru; Tanaka, Masayuki; Fukugita, Masataka; Kent, Steve; Finkbeiner, Douglas; Munn, Jeffrey A.; Pier, Jeffrey R.; Quinn, Tom; Hawley, Suzanne; Anderson, Scott; Kiuchi, Furea; Chen, Alex; Bushong, James; Sohi, Harkirat; Haggard, Daryl; Kimball, Amy; Barentine, John; Brewington, Howard; Harvanek, Mike; Kleinman, Scott; Krzesinski, Jurek; Long, Dan; Nitta, Atsuko; Snedden, Stephanie; Lee, Brian; Harris, Hugh; Brinkmann, Jonathan; Schneider, Donald P.; York, Donald G.; Prieto, Carlos AllendeUsing effective temperature and metallicity derived from SDSS spectra for similar to 60,000 F- and G-type main-sequence stars (0.2 < g - r < 0.6), we develop polynomial models for estimating these parameters from the SDSS u - g and g - r colors. These photometric estimates have similar error properties as those determined from SDSS spectra. We apply this method to SDSS photometric data for over 2 million F/G stars and measure the unbiased metallicity distribution for a complete volume-limited sample of stars at distances between 500 pc and 8 kpc. The metallicity distribution can be exquisitely modeled using two components with a spatially varying number ratio, which correspond to disk and halo. The two components also possess the kinematics expected for disk and halo stars. The metallicity of the halo component is spatially invariant, while the median disk metallicity smoothly decreases with distance from the Galactic plane from -0.6 at 500 pc to -0.8 beyond several kiloparsecs. The absence of a correlation between metallicity and kinematics for disk stars is in a conflict with the traditional decomposition in terms of thin and thick disks. We detect coherent substructures in the kinematics-metallicity space, such as the Monoceros stream, which rotates faster than the LSR, and has a median metallicity of [Fe/H] = -0.95, with an rms scatter of only similar to 0.15 dex. We extrapolate our results to the performance expected from the Large Synoptic Survey Telescope (LSST) and estimate that LSST will obtain metallicity measurements accurate to 0.2 dex or better, with proper-motion measurements accurate to similar to 0.5 mas yr(-1), for about 200 million F/G dwarf stars within a distance limit of similar to 100 kpc (g < 23.5).Item The Sloan Digital Sky Survey-II Supernova Survey: Technical Summary(2008-01) Frieman, Joshua A.; Bassett, Bruce; Becker, Andrew; Choi, Changsu; Cinabro, David; DeJongh, Fritz; Depoy, Darren L.; Dilday, Ben; Doi, Mamoru; Garnavich, Peter M.; Hogan, Craig J.; Holtzman, Jon; Im, Myungshin; Jha, Saurabh; Kessler, Richard; Konishi, Kohki; Lampeitl, Hubert; Marriner, John; Marshall, Jennifer L.; McGinnis, David; Miknaitis, Gajus; Nichol, Robert C.; Prieto, Jose Luis; Riess, Adam G.; Richmond, Michael W.; Romani, Roger; Sako, Masao; Schneider, Donald P.; Smith, Mathew; Takanashi, Naohiro; Tokita, Kouichi; van der Heyden, Kurt; Yasuda, Naoki; Zheng, Chen; Adelman-McCarthy, Jennifer; Annis, James; Assef, Roberto J.; Barentine, John; Bender, Ralf; Blandford, Roger D.; Boroski, William N.; Bremer, Malcolm; Brewington, Howard; Collins, Chris A.; Crotts, Arlin; Dembicky, Jack; Eastman, Jason; Edge, Alastair; Edmondson, Edmond; Elson, Edward; Eyler, Michael E.; Filippenko, Alexei V.; Foley, Ryan J.; Frank, Stephan; Goobar, Ariel; Gueth, Tina; Gunn, James E.; Harvanek, Michael; Hopp, Ulrich; Ihara, Yutaka; Ivezić, Želko; Kahn, Steven; Kaplan, Jared; Kent, Stephen; Ketzeback, William; Kleinman, Scott J.; Kollatschny, Wolfram; Kron, Richard G; Krzesiński, Jurek; Lamenti, Dennis; Leloudas, Giorgos; Lin, Huan; Long, Daniel C.; Lucey, John; Lupton, Robert H.; Malanushenko, Elena; Malanushenko, Viktor; McMillan, Russet J.; Mendez, Javier; Morgan, Christopher W.; Morokuma, Tomoki; Nitta, Atsuko; Ostman, Linda; Pan, Kaike; Rockosi, Constance M.; Romer, A. Kathy; Ruiz-Lapuente, Pilar; Saurage, Gabrelle; Schlesinger, Katie; Snedden, Stephanie A.; Sollerman, Jesper; Stoughton, Chris; Stritzinger, Maximilian; SubbaRao, Mark; Tucker, Douglas; Vaisanen, Petri; Watson, Linda C.; Watters, Shannon; Wheeler, J. Craig; Yanny, Brian; York, Donald; Barentine, John; Wheeler, J. CraigThe Sloan Digital Sky Survey-II (SDSS-II) has embarked on a multi-year project to identify and measure light curves for intermediate-redshift (0.05 < z < 0.35) Type la supernovae (SNe Ia) using repeated five-band (ugriz) imaging over an area of 300 sq. deg. The survey region is a stripe 2.5 degrees wide centered on the celestial equator in the Southern Galactic Cap that has been imaged numerous times in earlier years, enabling construction of a deep reference image for the discovery of new objects. Supernova imaging observations are being acquired between September I and November 30 of 2005-7. During the first two seasons, each region was imaged on average every five nights. Spectroscopic follow-up observations to determine supernova type and redshift are carried out on a large number of telescopes. In its first two three-month seasons, the survey has discovered and measured light curves for 327 spectroscopically confirmed SNe Ia, 30 probable SNe Ia, 14 confirmed SNe Ib/c, 32 confirmed SNe 11, plus a large number of photometrically identified SNe la, 94 of which have host-galaxy spectra taken so far. This paper provides an overview of the project and briefly describes the observations completed during the first two seasons of operation.