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The stellar metallicity distribution function of the galactic halo from sdss photometry

Title
The stellar metallicity distribution function of the galactic halo from sdss photometry
Authors
An D.Beers T.C.Johnson J.A.Pinsonneault M.H.Lee Y.S.Bovy J.Ivezic Z.Carollo D.Newby M.
Ewha Authors
안덕근
SCOPUS Author ID
안덕근scopus
Issue Date
2013
Journal Title
Astrophysical Journal
ISSN
0004-637XJCR Link
Citation
vol. 763, no. 1
Indexed
SCI; SCIE; SCOPUS WOS scopus
Abstract
We explore the stellar metallicity distribution function of the Galactic halo based on SDSS ugriz photometry. A set of stellar isochrones is calibrated using observations of several star clusters and validated by comparisons with medium-resolution spectroscopic values over a wide range of metal abundance. We estimate distances and metallicities for individual main-sequence stars in the multiply scanned SDSS Stripe 82, at heliocentric distances in the range 5-8 kpc and

b

> 35°, and find that the in situ photometric metallicity distribution has a shape that matches that of the kinematically selected local halo stars from Ryan & Norris. We also examine independent kinematic information from proper-motion measurements for high Galactic latitude stars in our sample. We find that stars with retrograde rotation in the rest frame of the Galaxy are generally more metal poor than those exhibiting prograde rotation, which is consistent with earlier arguments by Carollo et al. that the halo system comprises at least two spatially overlapping components with differing metallicity, kinematics, and spatial distributions. The observed photometric metallicity distribution and that of Ryan & Norris can be described by a simple chemical evolution model by Hartwick (or by a single Gaussian distribution); however, the suggestive metallicity-kinematic correlation contradicts the basic assumption in this model that the Milky Way halo consists primarily of a single stellar population. When the observed metallicity distribution is deconvolved using two Gaussian components with peaks at [Fe/H] ≈-1.7 and -2.3, the metal-poor component accounts for ∼20%-35% of the entire halo population in this distance range. © 2013 The American Astronomical Society. All rights reserved.
DOI
10.1088/0004-637X/763/1/65
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사범대학 > 과학교육과 > Journal papers
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