Age and Metallicity Analysis of the Small Magellanic Cloud from Star Clusters

We present metallicities for 15 Small Magellanic Cloud (SMC) star clusters. We add to this sample the ages and metallicities of 15 additional star clusters previously studied by Parisi et al. (2009) and Parisi et al. (2013), which were observed and analyzed following the same procedures as in the present work. Therefore, we compiled a sample of 30 SMC star clusters homogeneously studied, the largest sample to date. Metallicities are determined from the Calcium II triplet lines (CaT) in spectra obtained using the FORS2 multi-object spectrograph on the VLT (Paranal, Chile). Ages are determined from color-magnitude diagrams built from photometry of the pre-images. Using this sample, we analyze the chemical properties of the SMC, particularly the age-metallicity relation. We found three new old clusters which help to fill the so called SMC "age gap" between L 1 and NGC 121, the 2 oldest previously known clusters. These new old SMC clusters broadly increase our knowledge of the chemical evolution of this galaxy during the earliest epochs.