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arXiv · 1503.02110

Chemical Cartography with APOGEE: Metallicity Distribution Functions and the Chemical Structure of the Milky Way Disk

Michael R. Hayden·Jo Bovy·Jon A. Holtzman·David L. Nidever·Jonathan C. Bird·David H. Weinberg·Brett H. Andrews·Carlos Allende Prieto·Friedrich Anders·Timothy C. Beers·Dmitry Bizyaev·Cristina Chiappini·Katia Cunha·Peter Frinchaboy·Domingo A. García-Herńandez·Ana E. García Pérez·Léo Girardi·Paul Harding·Fred R. Hearty·Jennifer A. Johnson·Steven R. Majewski·Szabolcs Mészáros·Ivan Minchev·Robert O'Connell·Kaike Pan·Annie C. Robin·Ricardo P. Schiavon·Donald P. Schneider·Mathias Schultheis·Matthew Shetrone·Michael Skrutskie·Matthias Steinmetz·Verne Smith·Olga Zamora·Gail Zasowski
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Abstract

Using a sample of 69,919 red giants from the SDSS-III/APOGEE Data Release 12, we measure the distribution of stars in the [$\alpha$/Fe] vs. [Fe/H] plane and the metallicity distribution functions (MDF) across an unprecedented volume of the Milky Way disk, with radius $3 11$ kpc. The peak of the midplane MDF shifts to lower metallicity at larger $R$, reflecting the Galactic metallicity gradient. Most strikingly, the shape of the midplane MDF changes systematically with radius, with a negatively skewed distribution at $3 1$ kpc or [$\alpha$/Fe]$>0.18$, the MDF shows little dependence on $R$. The positive skewness of the outer disk MDF may be a signature of radial migration; we show that blurring of stellar populations by orbital eccentricities is not enough to explain the reversal of MDF shape but a simple model of radial migration can do so.

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Michael R. Hayden, Jo Bovy, Jon A. Holtzman, David L. Nidever, Jonathan C. Bird, David H. Weinberg, Brett H. Andrews, Carlos Allende Prieto, Friedrich Anders, Timothy C. Beers, Dmitry Bizyaev, Cristina Chiappini, Katia Cunha, Peter Frinchaboy, Domingo A. García-Herńandez, Ana E. García Pérez, Léo Girardi, Paul Harding, Fred R. Hearty, Jennifer A. Johnson, Steven R. Majewski, Szabolcs Mészáros, Ivan Minchev, Robert O'Connell, Kaike Pan, Annie C. Robin, Ricardo P. Schiavon, Donald P. Schneider, Mathias Schultheis, Matthew Shetrone, Michael Skrutskie, Matthias Steinmetz, Verne Smith, Olga Zamora, Gail Zasowski. 2015-03-07. Chemical Cartography with APOGEE: Metallicity Distribution Functions and the Chemical Structure of the Milky Way Disk. https://doi.org/10.1088/0004-637x/808/2/132

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