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Paper: Metallicities and Alpha-to-Iron Ratios in Globular Cluster Stars on a Homogeneous Scale: Search for Multiple Populations
Volume: 491, Fifty Years of Wide Field Studies in the Southern Hemisphere: Resolved Stellar Populations in the Galactic Bulge and the Magellanic Clouds
Page: 134
Authors: Dias, B.; Saviane, I.; Barbuy, B.; Held, E.; Da Costa, G.; Ortolani, S.; Vasquez, S.
Abstract: We are carrying out a survey of 51 poorly studied Milky Way globular clusters by means of spectroscopy of ∼20 red giant stars per cluster. Optical spectra (4600-5800 Å) were obtained with FORS2@VLT/ESO, at a resolution Δλ ∼ 2.5 Å. We used the ETOILE code to derive radial velocities, Teff, log g, [Fe/H], and [Mg/Fe] for each star by identifying the best fitted spectrum among a grid of stellar spectra. The stellar library can be a collection of observed or synthetic spectra. The main contributions of this work are to provide a homogeneous scale of [Fe/H], [Mg/Fe], and radial velocities for 51 clusters (in particular for the 29 distant and/or highly reddened ones), to provide a catalogue of confirmed member stars for each cluster, and to identify interesting clusters for follow-up with high resolution data (e.g., the massive clusters M 22 and NGC 5824, for which a spread in [Fe/H] was found).
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