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Characterizing epochs of star formation across the Milky Way disc using age-metallicity distributions of GALAH stars

Sahlholdt, Christian LU ; Feltzing, Sofia LU orcid and Feuillet, Diane LU orcid (2022) In Monthly Notices of the Royal Astronomical Society 510(4). p.4669-4688
Abstract
We provide a detailed map of the ages and metallicities of turn-off stars in the Milky Way disc based on data from GALAH DR3 and Gaia EDR3. From this map, we identify previously undetected features in the age-metallicity distribution of disc stars and interpret these results as indicating a three-phase formation history of the Milky Way. In the first phase, inner disc stars form along a single age-metallicity sequence and are today kinematically hot. The end of this phase is marked by a local minimum in the inner disc age distribution 10 Gyr ago. At this time, we find the stellar populations to transition from high to low alpha-element abundances and from high to low vertical velocity dispersion. In the second phase, stars form across the... (More)
We provide a detailed map of the ages and metallicities of turn-off stars in the Milky Way disc based on data from GALAH DR3 and Gaia EDR3. From this map, we identify previously undetected features in the age-metallicity distribution of disc stars and interpret these results as indicating a three-phase formation history of the Milky Way. In the first phase, inner disc stars form along a single age-metallicity sequence and are today kinematically hot. The end of this phase is marked by a local minimum in the inner disc age distribution 10 Gyr ago. At this time, we find the stellar populations to transition from high to low alpha-element abundances and from high to low vertical velocity dispersion. In the second phase, stars form across the disc with outwardly decreasing metallicity. In this phase, inner disc stars form at supersolar metallicities in a continuation of the early age-metallicity relation, while outer disc stars begin forming at metallicities at least 0.5 dex lower. Finally, the third phase is associated with a recent burst of star formation across the local disc marked by a local minimum in the age-metallicity distribution 4-6 Gyr ago. Future quantitative comparisons between the observed age-metallicity distribution and those of simulated galaxies could help constrain the processes driving each of the star formation phases. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Monthly Notices of the Royal Astronomical Society
volume
510
issue
4
pages
20 pages
publisher
Oxford University Press
external identifiers
  • scopus:85125129021
ISSN
1365-2966
DOI
10.1093/mnras/stab3681
language
English
LU publication?
yes
id
455aef8a-05cd-43ca-bcf1-b20663881032
date added to LUP
2022-03-03 13:37:32
date last changed
2024-04-18 08:24:30
@article{455aef8a-05cd-43ca-bcf1-b20663881032,
  abstract     = {{We provide a detailed map of the ages and metallicities of turn-off stars in the Milky Way disc based on data from GALAH DR3 and Gaia EDR3. From this map, we identify previously undetected features in the age-metallicity distribution of disc stars and interpret these results as indicating a three-phase formation history of the Milky Way. In the first phase, inner disc stars form along a single age-metallicity sequence and are today kinematically hot. The end of this phase is marked by a local minimum in the inner disc age distribution 10 Gyr ago. At this time, we find the stellar populations to transition from high to low alpha-element abundances and from high to low vertical velocity dispersion. In the second phase, stars form across the disc with outwardly decreasing metallicity. In this phase, inner disc stars form at supersolar metallicities in a continuation of the early age-metallicity relation, while outer disc stars begin forming at metallicities at least 0.5 dex lower. Finally, the third phase is associated with a recent burst of star formation across the local disc marked by a local minimum in the age-metallicity distribution 4-6 Gyr ago. Future quantitative comparisons between the observed age-metallicity distribution and those of simulated galaxies could help constrain the processes driving each of the star formation phases.}},
  author       = {{Sahlholdt, Christian and Feltzing, Sofia and Feuillet, Diane}},
  issn         = {{1365-2966}},
  language     = {{eng}},
  month        = {{03}},
  number       = {{4}},
  pages        = {{4669--4688}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{Characterizing epochs of star formation across the Milky Way disc using age-metallicity distributions of GALAH stars}},
  url          = {{http://dx.doi.org/10.1093/mnras/stab3681}},
  doi          = {{10.1093/mnras/stab3681}},
  volume       = {{510}},
  year         = {{2022}},
}