Analysis and calibration of CaII triplet spectroscopy of red giant branch stars from VLT/FLAMES observations

Battaglia, G.; Irwin, M.; Tolstoy, E.; Hill, V.; Helmi, A.; Letarte, B.; Jablonka, P.
Referencia bibliográfica

Monthly Notices of the Royal Astronomical Society, Volume 383, Issue 1, pp. 183-199.

Fecha de publicación:
1
2008
Número de autores
7
Número de autores del IAC
0
Número de citas
174
Número de citas referidas
152
Descripción
We demonstrate that low-resolution CaII triplet (CaT) spectroscopic estimates of the overall metallicity ([Fe/H]) of individual red giant branch (RGB) stars in two nearby dwarf spheroidal galaxies (dSphs) agree to +/-0.1-0.2 dex with detailed high-resolution spectroscopic determinations for the same stars over the range -2.5 < [Fe/H] < -0.5. For this study, we used a sample of 129 stars observed in low- and high-resolution modes with VLT/FLAMES in the Sculptor and Fornax dSphs. We also present the data-reduction steps we used in our low-resolution analysis and show that the typical accuracy of our velocity and CaT [Fe/H] measurement is ~2 km s-1 and 0.1 dex, respectively. We conclude that CaT-[Fe/H] relations calibrated on globular clusters can be applied with confidence to RGB stars in composite stellar populations over the range -2.5 < [Fe/H] < -0.5.