Advanced

The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk

Bergemann, M.; Ruchti, Gregory LU ; Serenelli, A.; Feltzing, Sofia LU ; Alves-Brito, A.; Asplund, M.; Bensby, Thomas LU ; Gruiters, P.; Heiter, U. and Hourihane, A., et al. (2014) In Astronomy & Astrophysics 565.
Abstract
We study the relationship between age, metallicity, and alpha-enhancement of FGK stars in the Galactic disk. The results are based upon the analysis of high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore the limitations of the observed dataset, i.e. the accuracy of stellar parameters and the selection effects that are caused by the photometric target preselection. We find that the colour and magnitude cuts in the survey suppress old metal-rich stars and young metal-poor stars. This suppression may be as high as 97% in some regions of the age-metallicity relationship. The dataset consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5 Gyr, Galactocentric distances from 6 kpc to 9.5 kpc, and vertical... (More)
We study the relationship between age, metallicity, and alpha-enhancement of FGK stars in the Galactic disk. The results are based upon the analysis of high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore the limitations of the observed dataset, i.e. the accuracy of stellar parameters and the selection effects that are caused by the photometric target preselection. We find that the colour and magnitude cuts in the survey suppress old metal-rich stars and young metal-poor stars. This suppression may be as high as 97% in some regions of the age-metallicity relationship. The dataset consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5 Gyr, Galactocentric distances from 6 kpc to 9.5 kpc, and vertical distances from the plane 0 < vertical bar Z vertical bar < 1.5 kpc. On this basis, we find that i) the observed age-metallicity relation is nearly flat in the range of ages between 0 Gyr and 8 Gyr; ii) at ages older than 9 Gyr, we see a decrease in [Fe/H] and a clear absence of metal-rich stars; this cannot be explained by the survey selection functions; iii) there is a significant scatter of [Fe/H] at any age; and iv) [Mg/Fe] increases with age, but the dispersion of [Mg/Fe] at ages > 9 Gyr is not as small as advocated by some other studies. In agreement with earlier work, we find that radial abundance gradients change as a function of vertical distance from the plane. The [Mg/Fe] gradient steepens and becomes negative. In addition, we show that the inner disk is not only more alpha-rich compared to the outer disk, but also older, as traced independently by the ages and Mg abundances of stars. (Less)
Please use this url to cite or link to this publication:
author
, et al. (More)
(Less)
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
stars: abundances, stars: fundamental parameters, solar neighborhood, Galaxy: disk, Galaxy: formation, surveys
in
Astronomy & Astrophysics
volume
565
publisher
EDP Sciences
external identifiers
  • wos:000336730900089
  • scopus:84900811451
ISSN
0004-6361
DOI
10.1051/0004-6361/201423456
language
English
LU publication?
yes
id
30280c3b-648d-4200-a8d6-f643703e4ed9 (old id 4552152)
date added to LUP
2014-07-17 09:41:43
date last changed
2017-11-05 03:52:28
@article{30280c3b-648d-4200-a8d6-f643703e4ed9,
  abstract     = {We study the relationship between age, metallicity, and alpha-enhancement of FGK stars in the Galactic disk. The results are based upon the analysis of high-resolution UVES spectra from the Gaia-ESO large stellar survey. We explore the limitations of the observed dataset, i.e. the accuracy of stellar parameters and the selection effects that are caused by the photometric target preselection. We find that the colour and magnitude cuts in the survey suppress old metal-rich stars and young metal-poor stars. This suppression may be as high as 97% in some regions of the age-metallicity relationship. The dataset consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5 Gyr, Galactocentric distances from 6 kpc to 9.5 kpc, and vertical distances from the plane 0 &lt; vertical bar Z vertical bar &lt; 1.5 kpc. On this basis, we find that i) the observed age-metallicity relation is nearly flat in the range of ages between 0 Gyr and 8 Gyr; ii) at ages older than 9 Gyr, we see a decrease in [Fe/H] and a clear absence of metal-rich stars; this cannot be explained by the survey selection functions; iii) there is a significant scatter of [Fe/H] at any age; and iv) [Mg/Fe] increases with age, but the dispersion of [Mg/Fe] at ages &gt; 9 Gyr is not as small as advocated by some other studies. In agreement with earlier work, we find that radial abundance gradients change as a function of vertical distance from the plane. The [Mg/Fe] gradient steepens and becomes negative. In addition, we show that the inner disk is not only more alpha-rich compared to the outer disk, but also older, as traced independently by the ages and Mg abundances of stars.},
  articleno    = {A89},
  author       = {Bergemann, M. and Ruchti, Gregory and Serenelli, A. and Feltzing, Sofia and Alves-Brito, A. and Asplund, M. and Bensby, Thomas and Gruiters, P. and Heiter, U. and Hourihane, A. and Korn, A. and Lind, K. and Marino, A. and Jofre, P. and Nordlander, T. and Ryde, Nils and Worley, C. C. and Gilmore, G. and Randich, S. and Ferguson, A. M. N. and Jeffries, R. D. and Micela, G. and Negueruela, I. and Prusti, T. and Rix, H. -W. and Vallenari, A. and Alfaro, E. J. and Allende Prieto, C. and Bragaglia, A. and Koposov, S. E. and Lanzafame, A. C. and Pancino, E. and Recio-Blanco, A. and Smiljanic, R. and Walton, N. and Costado, M. T. and Franciosini, E. and Hill, V. and Lardo, C. and de Laverny, P. and Magrini, L. and Maiorca, E. and Masseron, T. and Morbidelli, L. and Sacco, G. and Kordopatis, G. and Tautvaisiene, G.},
  issn         = {0004-6361},
  keyword      = {stars: abundances,stars: fundamental parameters,solar neighborhood,Galaxy: disk,Galaxy: formation,surveys},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {The Gaia-ESO Survey: radial metallicity gradients and age-metallicity relation of stars in the Milky Way disk},
  url          = {http://dx.doi.org/10.1051/0004-6361/201423456},
  volume       = {565},
  year         = {2014},
}