The Magellanic Cloud?s Star Cluster Populations: The SMC

A.E. PIATTI

Fifty Years of Wide Field Studies in the Southern Hemisphere

Astronomical Society of the Pacific

Año: 2015; p. 227 - 234

               We present results based on observations carried out with the CTIO 4-mBlanco telescope and the attached MOSAIC II camera of a large sample of unstudiedor poorly studied candidate star clusters in the Small Magellanic Cloud (SMC). We firstcleaned the color-magnitude diagrams (CMDs) of the unavoidable stellar field contam-ination by taking advantage of a procedure that makes use of variable size CMD cells.In this way, stochastic effects in the cluster CMDs caused by the presence of isolatedbright stars and numerous relatively faint field stars, have successfully been eliminated.Our results suggest that a percentage of the studied candidate star clusters do appearto be genuine physical systems. However, the ages previously derived for some of thestudied candidate clusters mostly reflect those of the composite stellar populations ofthe SMC field. Finally, by using the spatial distribution in the SMC of possible non-clusters, we statistically decontaminated the SMC cluster system. We found that thereis no clear difference between the expected and observed cluster spatial distributions,but a difference at a 2 sigma level in the central regions would become visible if non-clusters are assumed to be ≈ 20% of the cataloged sample.