Spectroscopic study of star clusters in the Small Magellanic Cloud: star formation history

CLARIÁ, J. J.; PIATTI, A. E.; SANTOS, J. F. C., JR.; BICA, E.; AHUMADA, A. V.; PARISI, M. C.

La Plata - Argentina

Congreso; 48 Reunión de la Asociación Argentina de Astronomía; 2005

We present integrated spectra in the range (3600-6800) A for 18 concentrated clusters of the Small Magellanic Cloud (SMC). By using the template matching and equivalent width methods, ages and metallicities were respectively determined and a very good agreement between ages derived from both methods was found. Combining the present sample with 19 additional SMC clusters whose ages and metallicities were put onto a homogeneous scale, we analyze the clusters´ age and metallicity distributions. By considering the deprojected distances of the clusters from the SMC center instead of their projections onto the right ascension and declination axes, the ensuing analysis seems to indicate that the SMC inner disk could have been the result of a cluster formation episode which reached a peak ~ 2.5 Gyr ago. Evidence for a metallicity gradient in the SMC disk is also presented.We analyze the clusters´ age and metallicity distributions. By considering the deprojected distances of the clusters from the SMC center instead of their projections onto the right ascension and declination axes, the ensuing analysis seems to indicate that the SMC inner disk could have been the result of a cluster formation episode which reached a peak ~2.5 Gyr ago. Evidence for a metallicity gradient in the SMC disk is also presented.