Bibcode
DOI
Tolstoy, Eline; Irwin, M. J.; Helmi, A.; Battaglia, G.; Jablonka, P.; Hill, V.; Venn, K. A.; Shetrone, M. D.; Letarte, B.; Cole, A. A.; Primas, F.; Francois, P.; Arimoto, N.; Sadakane, K.; Kaufer, A.; Szeifert, T.; Abel, T.
Bibliographical reference
The Astrophysical Journal, Volume 617, Issue 2, pp. L119-L122.
Advertised on:
12
2004
Journal
Citations
330
Refereed citations
277
Description
We have found evidence for the presence of two distinct ancient stellar
components (both >=10 Gyr old) in the Sculptor dwarf spheroidal
galaxy. We used the ESO Wide Field Imager in conjunction with the Very
Large Telescope/FLAMES spectrograph to study the properties of the
resolved stellar population of Sculptor out to and beyond the tidal
radius. We find that two components are discernible in the spatial
distribution of horizontal branch stars in our imaging and in the [Fe/H]
and vhel distributions for our large sample of spectroscopic
measurements. They can be generally described as a ``metal-poor''
component ([Fe/H]<-1.7) and a ``metal-rich'' component
([Fe/H]>-1.7). The metal-poor stars are more spatially extended than
the metal-rich stars, and they also appear to be kinematically distinct.
These results provide insight into the formation processes of small
systems in the early universe and the conditions found there. Even this
simplest of galaxies appears to have had a surprisingly complex early
evolution.
Based on FLAMES observations collected at the ESO, proposals 71.B-0641
and 171.B-0588.