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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 421625.0, MPI für Astronomie / Publikationen_mpia
The milky way tomography with SDSS. II. Stellar metallicity
Authors:Ivezic, Zeljko; Sesar, Branimir; Juric, Mario; Bond, Nicholas; Dalcanton, Julianne; Rockosi, Constance M.; Yanny, Brian; Newberg, Heidi J.; Beers, Timothy C.; Allende Prieto, Carlos; Wilhelm, Ron; Lee, Young Sun; Sivarani, Thirupathi; Norris, John E.; Bailer-Jones, Coryn A. L.; Re Fiorentin, Paola; 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.
Date of Publication (YYYY-MM-DD):2008
Title of Journal:The Astrophysical Journal
Start Page:287
End Page:325
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:Using effective temperature and metallicity derived from SDSS spectra for ~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 ~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 ~0.5 mas yr-1, for about 200 million F/G dwarf stars within a distance limit of ~100 kpc (g<23.5).
Free Keywords:Galaxy: Halo; Galaxy: Kinematics and Dynamics; Galaxy: Stellar Content; Galaxy: Structure; Methods: Data Analysis; Stars: Statistics
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/abs/2008ApJ...684..287I [ID No:1]
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