Dating compact star clusters in the Small Magellanic Cloud by means of integrated spectra

TALAVERA, M. L.; AHUMADA, A. V.; CLARIÁ, J. J.; SANTOS, J. F. C., JR.; BICA, E.; TORRES, M. C.

Isla de Margarita, Venezuela

Congreso; XII Latin American IAU Regional Meeting; 2007

We present Flux-calibrated integrated spectra in the optical range for 12 compact Small Magellanic Cloud (SMC) star clusters, approximately half of which are unstudied objects. The Sample includes objects in the surroundings and main body of the SMC. Cluster reddening values are estimated by interpolation between the extinction maps of Burnstein & Heiles (1982, AJ, 87, 1165). We used two different procedures to derive cluster ages: (i) template matching, and (ii) equivalent width (EW) method, in which diagnostic diagrams involving the sum of EWs of selected spectral lines were employed together with their calibrations with age and metallicity. A good agreement between ages derived from both procedures was found. The derived foreground E(B - V) values are in the small range 0.03 ≤ E(B-V) ≤ 0.06, while ages vary from ˜ 10 Myr in Bruck 164 to ˜ 400 Myr in IC 1641. The present data constitute a spectral library at the metallicity level of SMC clusters.