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A Tale of Two Disks : Mapping the Milky Way with the Final Data Release of APOGEE

Imig, Julie ; Price, Cathryn ; Holtzman, Jon A. ; Stone-Martinez, Alexander ; Majewski, Steven R. ; Weinberg, David H. ; Johnson, Jennifer A. ; Allende Prieto, Carlos ; Beaton, Rachael L. and Beers, Timothy C. , et al. (2023) In Astrophysical Journal 954(2).
Abstract

We present new maps of the Milky Way disk showing the distribution of metallicity ([Fe/H]), α-element abundances ([Mg/Fe]), and stellar age, using a sample of 66,496 red giant stars from the final data release (DR17) of the Apache Point Observatory Galactic Evolution Experiment survey. We measure radial and vertical gradients, quantify the distribution functions for age and metallicity, and explore chemical clock relations across the Milky Way for the low-α disk, high-α disk, and total population independently. The low-α disk exhibits a negative radial metallicity gradient of -0.06 ± 0.001 dex kpc-1, which flattens with distance from the midplane. The high-α disk shows a flat radial gradient in metallicity and age across nearly all... (More)

We present new maps of the Milky Way disk showing the distribution of metallicity ([Fe/H]), α-element abundances ([Mg/Fe]), and stellar age, using a sample of 66,496 red giant stars from the final data release (DR17) of the Apache Point Observatory Galactic Evolution Experiment survey. We measure radial and vertical gradients, quantify the distribution functions for age and metallicity, and explore chemical clock relations across the Milky Way for the low-α disk, high-α disk, and total population independently. The low-α disk exhibits a negative radial metallicity gradient of -0.06 ± 0.001 dex kpc-1, which flattens with distance from the midplane. The high-α disk shows a flat radial gradient in metallicity and age across nearly all locations of the disk. The age and metallicity distribution functions shift from negatively skewed in the inner Galaxy to positively skewed at large radius. Significant bimodality in the [Mg/Fe]-[Fe/H] plane and in the [Mg/Fe]-age relation persist across the entire disk. The age estimates have typical uncertainties of ∼0.15 in log(age) and may be subject to additional systematic errors, which impose limitations on conclusions drawn from this sample. Nevertheless, these results act as critical constraints on galactic evolution models, constraining which physical processes played a dominant role in the formation of the Milky Way disk. We discuss how radial migration predicts many of the observed trends near the solar neighborhood and in the outer disk, but an additional more dramatic evolution history, such as the multi-infall model or a merger event, is needed to explain the chemical and age bimodality elsewhere in the Galaxy.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Astrophysical Journal
volume
954
issue
2
article number
124
publisher
American Astronomical Society
external identifiers
  • scopus:85175204113
ISSN
0004-637X
DOI
10.3847/1538-4357/ace9b8
language
English
LU publication?
yes
id
b85bf0bd-e4e7-4f3e-8853-fff7822b53fa
date added to LUP
2024-01-12 09:07:48
date last changed
2024-02-28 00:10:05
@article{b85bf0bd-e4e7-4f3e-8853-fff7822b53fa,
  abstract     = {{<p>We present new maps of the Milky Way disk showing the distribution of metallicity ([Fe/H]), α-element abundances ([Mg/Fe]), and stellar age, using a sample of 66,496 red giant stars from the final data release (DR17) of the Apache Point Observatory Galactic Evolution Experiment survey. We measure radial and vertical gradients, quantify the distribution functions for age and metallicity, and explore chemical clock relations across the Milky Way for the low-α disk, high-α disk, and total population independently. The low-α disk exhibits a negative radial metallicity gradient of -0.06 ± 0.001 dex kpc-1, which flattens with distance from the midplane. The high-α disk shows a flat radial gradient in metallicity and age across nearly all locations of the disk. The age and metallicity distribution functions shift from negatively skewed in the inner Galaxy to positively skewed at large radius. Significant bimodality in the [Mg/Fe]-[Fe/H] plane and in the [Mg/Fe]-age relation persist across the entire disk. The age estimates have typical uncertainties of ∼0.15 in log(age) and may be subject to additional systematic errors, which impose limitations on conclusions drawn from this sample. Nevertheless, these results act as critical constraints on galactic evolution models, constraining which physical processes played a dominant role in the formation of the Milky Way disk. We discuss how radial migration predicts many of the observed trends near the solar neighborhood and in the outer disk, but an additional more dramatic evolution history, such as the multi-infall model or a merger event, is needed to explain the chemical and age bimodality elsewhere in the Galaxy.</p>}},
  author       = {{Imig, Julie and Price, Cathryn and Holtzman, Jon A. and Stone-Martinez, Alexander and Majewski, Steven R. and Weinberg, David H. and Johnson, Jennifer A. and Allende Prieto, Carlos and Beaton, Rachael L. and Beers, Timothy C. and Bizyaev, Dmitry and Blanton, Michael R. and Brownstein, Joel R. and Cunha, Katia and Fernández-Trincado, José G. and Feuillet, Diane K. and Hasselquist, Sten and Hayes, Christian R. and Jönsson, Henrik and Lane, Richard R. and Lian, Jianhui and Mészáros, Szabolcs and Nidever, David L. and Robin, Annie C. and Shetrone, Matthew and Smith, Verne and Wilson, John C.}},
  issn         = {{0004-637X}},
  language     = {{eng}},
  month        = {{09}},
  number       = {{2}},
  publisher    = {{American Astronomical Society}},
  series       = {{Astrophysical Journal}},
  title        = {{A Tale of Two Disks : Mapping the Milky Way with the Final Data Release of APOGEE}},
  url          = {{http://dx.doi.org/10.3847/1538-4357/ace9b8}},
  doi          = {{10.3847/1538-4357/ace9b8}},
  volume       = {{954}},
  year         = {{2023}},
}