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Analysis and calibration of Ca ii triplet spectroscopy of red giant branch stars from VLT/FLAMES observations |
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| Authors: | G Battaglia M Irwin E Tolstoy V Hill A Helmi B Letarte P Jablonka |
| Institution: | Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, the Netherlands;Institute of Astronomy, Madingley Road, Cambridge CB3 0HA;GEPI, Observatoire de Paris, CNRS, Universit Paris Diderot;Place Jules Janssen 92190 Meudon, France;Caltech Astronomy, MC105-24, Pasadena, CA 91125, USA;Observatoire de Genève, Laboratoire d'Astrophysique de l'Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1290 Sauverny, Switzerland |
| Abstract: | We demonstrate that low-resolution Ca ii 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 |
| Keywords: | techniques: spectroscopic stars: abundances galaxies: dwarf galaxies: star clusters |