Bibcode
Carrera, R.; Gallart, C.; Hardy, Eduardo; Aparicio, A.; Zinn, R.
Bibliographical reference
The Astronomical Journal, Volume 135, Issue 3, pp. 836-849 (2008).
Advertised on:
3
2008
Citations
123
Refereed citations
107
Description
Ca II triplet spectroscopy has been used to derive stellar metallicities
for individual stars in four Large Magellanic Cloud fields situated at
galactocentric distances of 3°, 5°, 6°, and 8° to the
north of the bar. Observed metallicity distributions show a well-defined
peak, with a tail toward low metallicities. The mean metallicity remains
constant until 6° ([Fe/H] ~ -0.5 dex), while for the outermost
field, at 8°, the mean metallicity is substantially lower than in
the rest of the disk ([Fe/H] ~ -0.8 dex). The combination of
spectroscopy with deep CCD photometry has allowed us to break the RGB
age-metallicity degeneracy and compute the ages for the objects observed
spectroscopically. The obtained age-metallicity relationships (AMRs) for
our four fields are statistically indistinguishable. We conclude that
the lower mean metallicity in the outermost field is a consequence of it
having a lower fraction of intermediate-age stars, which are more
metal-rich than the older stars. The disk AMR is similar to that for
clusters. However, the lack of objects with ages between 3 and 10 Gyr is
not observed in the field population. Finally, we used data from the
literature to derive consistently the AMR of the bar. Simple chemical
evolution models have been used to reproduce the observed AMRs with the
purpose of investigating which mechanism has participated in the
evolution of the disk and bar. We find that while the disk AMR is well
reproduced by close-box models or models with a small degree of outflow,
that of the bar is only reproduced by models with combination of infall
and outflow.
Related projects
Milky Way and Nearby Galaxies
The general aim of the project is to research the structure, evolutionary history and formation of galaxies through the study of their resolved stellar populations, both from photometry and spectroscopy. The group research concentrates in the most nearby objects, namely the Local Group galaxies including the Milky Way and M33 under the hypothesis
Martín
López Corredoira