Kinematics and metallicity relations for dwarf galaxies in the Local Group

Battaglia, Giuseppina; Tolstoy, Eline; Helmi, Amina; Irwin, Mike
Bibliographical reference

"Proceedings of "Baryons in Dark Matter Halos". Novigrad, Croatia, 5-9 Oct 2004. Editors: R. Dettmar, U. Klein, P. Salucci. Published by SISSA, Proceedings of Science, http://pos.sissa.it, p.54.1"

Advertised on:
12
2004
Number of authors
4
IAC number of authors
0
Citations
0
Refereed citations
0
Description
We present the first results of intermediate resolution spectral observations in the CaII triplet region obtained with VLT/FLAMES for 3 dwarf spheroidal galaxies in the Local Group: Sculptor, Fornax and Sextans. For each galaxy, we obtained accurate velocity and metallicity measurements for hundreds of stars out to and beyond the tidal radius: this was not possible with previous observations. Therefore, with this work we are able to investigate the presence of gradients in the kinematic and metallicity properties and explore possible links between them. In each galaxy, we find clear evidence for the presence of two distinct stellar components with different spatial distribution and kinematics: the metal rich component is more centrally concen- trated and kinematically colder than the metal poor one. These findings show that even dSphs, the simplest galaxies known, have undergone a complex evolution.