A Photometric Metallicity Estimate of the Virgo Stellar Overdensity
Abstract
We determine photometric metal abundance estimates for individual main-sequence stars in the Virgo Overdensity (VOD), which covers almost 1000 deg^2 on the sky, based on a calibration of the metallicity sensitivity of stellar isochrones in the gri filter passbands using field stars with well-determined spectroscopic metal abundances. Despite the low precision of the method for individual stars, we derive [Fe/H] = –2.0 ± 0.1(internal) ± 0.5(systematic) for the metal abundance of the VOD from photometric measurements of 0.7 million stars in the northern Galactic hemisphere with heliocentric distances from ~10 kpc to ~20 kpc. The metallicity of the VOD is indistinguishable, within Δ[Fe/H] ≤ 0.2, from that of field halo stars covering the same distance range. This initial application suggests that the Sloan Digital Sky Survey gri passbands can be used to probe the properties of main-sequence stars beyond ~10 kpc, complementing studies of nearby stars from more metallicity-sensitive color indices that involve the u passband.
Additional Information
© 2009. The American Astronomical Society. All rights reserved. Received 2009 July 4; accepted 2009 November 5; published 2009 November 24. We thank James Bullock, Željko Ivezíc, Heather Morrison, and Katie Schlesinger for useful discussions. T.C.B. and Y.S.L. acknowledge partial funding of this work from grant PHY 08- 22648: Physics Frontiers Center/Joint Institute for Nuclear Astrophysics (JINA), awarded by the U.S. National Science Foundation. Funding for the SDSS and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web site is http://www.sdss.org/. The SDSS is managed by the Astrophysical Research Consortium for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck Institute for Astronomy (MPIA), the Max-Planck Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington.Attached Files
Published - An2009p6573Astrophys_J_Lett.pdf
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Additional details
- Eprint ID
- 17140
- Resolver ID
- CaltechAUTHORS:20100112-090751137
- PHY 08- 22648
- NSF
- Physics Frontiers Center/Joint Institute for Nuclear Astrophysics
- Alfred P. Sloan Foundation
- Department of Energy (DOE)
- NASA
- Japanese Monbukagakusho
- Max Planck Society
- Higher Education Funding Council for England
- Created
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2010-01-25Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field