Hints for multiple populations in intermediate-age clusters of the Small Magellanic Cloud

A.E. PIATTI

ASTRONOMICAL JOURNAL

IOP PUBLISHING LTD

Lugar: Londres; Año: 2018 vol. 156 p. 206 - 218

0004-6256

We report on the magnitude of the intrinsic [Fe/H] spreadin the Small Magellanic Cloud (SMC) intermediate-age massive clusters NGC,339, 361, Lindsay,1and 113, respectively. In order to measure the cluster metallicity dispersions, we used accurate Str"omgren photometry of carefully selected cluster red giant branch (RGB) stars. We  determined the Fe-abundance spreads by employing a maximum likelihood approach. The spreads obtained using the more accuratephotometry of the brighter RGB stars resulted to be marginal ($sim$ 0.05$pm$0.03 dex)for NGC,339 and NGC,361, while for Lindsay,1 and Lindsay,113 we obtained metallicity spreads of 0.00$pm$0.04 dex. From these results, we speculated with the possibility that NGC,361 is added to the group of four SMC clusters with observational evidence of multiple populations (MPs). Furthermore, in the context of the present debate about theexistence of Fe-abundance inhomogeneities among old clusters with MPs, these outcomes put new constrains to recent theoretical speculations for making this phenomenon visible.