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A possible age-metallicity relation in the Galactic thick disk?

Bensby, Thomas LU ; Feltzing, Sofia LU and Lundström, Ingemar LU (2004) In Astronomy and Astrophysics 421. p.969-976
Abstract
A sample of 229 nearby thick disk stars has been used to investigate theexistence of an age-metallicity relation (AMR) in the Galactic thickdisk. The results indicate that that there is indeed an age-metallicityrelation present in the thick disk. By dividing the stellar sample intosub-groups, separated by 0.1 dex in metallicity, we show that the medianage decreases by about 5-7 Gyr when going from [Fe/H] ≈ -0.8 to[Fe/H] ≈ -0.1. Combining our results with our newly publishedα-element trends for a local sample of thick disk stars that showsignatures from supernovae type Ia (SN Ia), we draw the conclusion thatthe time-scale for the peak of the SN Ia rate is of the order of 3-4 Gyrin the thick disk. The tentative evidence for a thick disk AMR... (More)
A sample of 229 nearby thick disk stars has been used to investigate theexistence of an age-metallicity relation (AMR) in the Galactic thickdisk. The results indicate that that there is indeed an age-metallicityrelation present in the thick disk. By dividing the stellar sample intosub-groups, separated by 0.1 dex in metallicity, we show that the medianage decreases by about 5-7 Gyr when going from [Fe/H] ≈ -0.8 to[Fe/H] ≈ -0.1. Combining our results with our newly publishedα-element trends for a local sample of thick disk stars that showsignatures from supernovae type Ia (SN Ia), we draw the conclusion thatthe time-scale for the peak of the SN Ia rate is of the order of 3-4 Gyrin the thick disk. The tentative evidence for a thick disk AMR that wepresent here also has implications for the thick disk formationscenario; star-formation must have been an ongoing process for severalbillion years. This appears to strengthen the hypothesis that the thickdisk originated from a merger event with a companion galaxy that puffedup a pre-existing thin disk.Based on data obtained with the Hipparcos satellite. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
keywords
stars: Hertzsprung-Russell (HR) and C-M diagrams, stars: kinematics, Galaxy: disk, Galaxy: formation, Galaxy: solar neighbourhood, Galaxy: kinematics and dynamics
in
Astronomy and Astrophysics
volume
421
pages
969 - 976
publisher
EDP Sciences
external identifiers
  • wos:000223249700017
  • scopus:3142680399
ISSN
1432-0746
DOI
10.1051/0004-6361:20035957
language
English
LU publication?
yes
id
2c0409d9-99b5-4765-8541-1abcdfc0cee9 (old id 134119)
date added to LUP
2007-07-12 14:05:07
date last changed
2017-10-22 04:42:18
@article{2c0409d9-99b5-4765-8541-1abcdfc0cee9,
  abstract     = {A sample of 229 nearby thick disk stars has been used to investigate theexistence of an age-metallicity relation (AMR) in the Galactic thickdisk. The results indicate that that there is indeed an age-metallicityrelation present in the thick disk. By dividing the stellar sample intosub-groups, separated by 0.1 dex in metallicity, we show that the medianage decreases by about 5-7 Gyr when going from [Fe/H] ≈ -0.8 to[Fe/H] ≈ -0.1. Combining our results with our newly publishedα-element trends for a local sample of thick disk stars that showsignatures from supernovae type Ia (SN Ia), we draw the conclusion thatthe time-scale for the peak of the SN Ia rate is of the order of 3-4 Gyrin the thick disk. The tentative evidence for a thick disk AMR that wepresent here also has implications for the thick disk formationscenario; star-formation must have been an ongoing process for severalbillion years. This appears to strengthen the hypothesis that the thickdisk originated from a merger event with a companion galaxy that puffedup a pre-existing thin disk.Based on data obtained with the Hipparcos satellite.},
  author       = {Bensby, Thomas and Feltzing, Sofia and Lundström, Ingemar},
  issn         = {1432-0746},
  keyword      = {stars: Hertzsprung-Russell (HR) and C-M diagrams,stars: kinematics,Galaxy: disk,Galaxy: formation,Galaxy: solar neighbourhood,Galaxy: kinematics and dynamics},
  language     = {eng},
  pages        = {969--976},
  publisher    = {EDP Sciences},
  series       = {Astronomy and Astrophysics},
  title        = {A possible age-metallicity relation in the Galactic thick disk?},
  url          = {http://dx.doi.org/10.1051/0004-6361:20035957},
  volume       = {421},
  year         = {2004},
}