文章基本信息

标题：Hints of Multiple Populations in Intermediate-age Clusters of the Small Magellanic Cloud
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作者：Andrés E. Piatti
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2018
卷号：156
期号：5
页码：1-12
DOI：10.3847/1538-3881/aae38d
语种：English
出版社：American Institute of Physics
摘要：We report on the magnitude of the intrinsic [Fe/H] spread in the Small Magellanic Cloud (SMC) intermediate-age massive clusters NGC 339, 361, Lindsay 1 and 113, respectively. In order to measure the cluster metallicity dispersions, we used accurate Strömgren 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 accurate photometry of the brighter RGB stars resulted to be marginal (∼0.05 ±0.03 dex) for NGC 339 and NGC 361, while for Lindsay 1 and Lindsay 113, we obtained metallicity spreads of 0.00±0.04 dex. From these results, we speculate 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 the existence of Fe-abundance inhomogeneities among old clusters with MPs, these outcomes place new constrains on recent theoretical speculations for making this phenomenon visible.
关键词：galaxies: individual (SMC);Magellanic Clouds;techniques: photometric