期刊
ASTROPHYSICAL JOURNAL
卷 761, 期 2, 页码 -出版社
IOP Publishing Ltd
DOI: 10.1088/0004-637X/761/2/160
关键词
Galaxy: disk; Galaxy: evolution; Galaxy: stellar content; Galaxy: structure; stars: abundances; surveys
资金
- NSF [AST-0807997, AST-0607482]
- David and Lucille Packard Foundation
- Physics Frontiers Center/Joint Institute for Nuclear Astrophysics (JINA) [PHY 08-22648]
- U.S. National Science Foundation
- Alfred P. Sloan Foundation
- National Science Foundation
- U.S. Department of Energy Office of Science
- University of Arizona
- Brazilian Participation Group
- Brookhaven National Laboratory
- University of Cambridge
- University of Florida
- French Participation Group
- German Participation Group
- Instituto de Astrofisica de Canarias
- Michigan State/Notre Dame/JINA Participation Group
- Johns Hopkins University
- Lawrence Berkeley National Laboratory
- Max Planck Institute for Astrophysics
- New Mexico State University
- New York University
- Ohio State University
- Pennsylvania State University
- University of Portsmouth
- Princeton University
- Spanish Participation Group
- University of Tokyo
- University of Utah
- Vanderbilt University
- University of Virginia
- University of Washington
- Yale University
- [AST-1009886]
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [1009886] Funding Source: National Science Foundation
We present the metallicity distribution function (MDF) for 24,270 G and 16,847 K dwarfs at distances from 0.2 to 2.3 kpc from the Galactic plane, based on spectroscopy from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) survey. This stellar sample is significantly larger in both number and volume than previous spectroscopic analyses, which were limited to the solar vicinity, making it ideal for comparison with local volume-limited samples and Galactic models. For the first time, we have corrected the MDF for the various observational biases introduced by the SEGUE target-selection strategy. SEGUE is particularly notable for its sample of K dwarfs, which are too faint to examine spectroscopically far from the solar neighborhood. The MDF of both spectral types becomes more metal-poor with increasing vertical bar Z vertical bar, which reflects the transition from a sample with small [alpha/Fe] values at small heights to one with enhanced [alpha/Fe] above 1 kpc. Comparison of our SEGUE distributions to those of two different MilkyWay models reveals that both are more metal-rich than our observed distributions at all heights above the plane. Our unbiased observations of G and K dwarfs provide valuable constraints over the vertical bar Z vertical bar-height range of the Milky Way disk for chemical and dynamical Galaxy evolution models, previously only calibrated to the solar neighborhood, with particular utility for thin- and thick-disk formation models.
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