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Home Search Quick Search Advanced Fulltext Browse Collections Persons My eDoc Session History Login Name: Password: Documentation Help Support Wiki Direct access to document ID:	Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents ID: 308510.0, MPI für Astronomie / Publikationen_mpia A curious Milky Way satellite in Ursa Major Authors: Zucker, D. B.; Belokurov, V.; Evans, N. W.; Kleyna, J. T.; Irwin, M. J.; Wilkinson, M. I.; Fellhauer, M.; Bramich, D. M.; Gilmore, G.; Newberg, H. J.; Yanny, B.; Smith, J. A.; Hewett, P. C.; Bell, E. F.; Rix, H. W.; Gnedin, O. Y.; Vidrih, S.; Wyse, R. F. G.; Willman, B.; Grebel, E. K.; Schneider, D. P.; Beers, T. C.; Kniazev, A. Y.; Barentine, J. C.; Brewington, H.; Brinkmann, J.; Harvanek, M.; Kleinman, S. J.; Krzesinski, J.; Long, D.; Nitta, A.; Snedden, S. A. Date of Publication (YYYY-MM-DD): 2006 Journal Abbrev.: The Astrophysical Journal Volume: 650 Start Page: L41 End Page: L44 Audience: Not Specified Abstract / Description: In this Letter, we study a localized stellar overdensity in the constellation of Ursa Major, first identified in Sloan Digital Sky Survey (SDSS) data and subsequently followed up with Subaru imaging. Its color-magnitude diagram (CMD) shows a well-defined subgiant branch, main sequence, and turnoff, from which we estimate a distance of ~30 kpc and a projected size of ~250×125 pc2. The CMD suggests a composite population with some range in metallicity and/or age. Based on its extent and stellar population, we argue that this is a previously unknown satellite galaxy of the Milky Way, hereby named Ursa Major II (UMa II) after its constellation. Using SDSS data, we find an absolute magnitude of MV~-3.8, which would make it the faintest known satellite galaxy. UMa II's isophotes are irregular and distorted with evidence for multiple concentrations; this suggests that the satellite is in the process of disruption. Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Free Keywords: Galaxies: Dwarf; galaxies: individual (Ursa Major II); Galaxies: Local Group External Publication Status: published Document Type: Article Communicated by: N. N. Affiliations: MPI für Astronomie Identifiers: URL:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bi... The scope and number of records on eDoc is subject to the collection policies defined by each institute - see "info" button in the collection browse view.