STELLAR POPULATIONS IN THE OUTSKIRTS OF THE SMALL MAGELLANIC CLOUD: NO OUTER EDGE YET

摘要

We report the detection of intermediate-age and old stars belonging to the SMC at 6.5 kpc from the SMC center in the southern direction. We show, from the analysis of three high-quality 34′ x 33′ CMDs, that the age composition of the stellar population is similar at galactocentric distances of ～4.7, ～5.6, and ～6.5 kpc. The surface brightness profile of the SMC follows an exponential law, with no evidence of truncation, all the way out to 6.5 kpc. These results, taken together, suggest that the SMC "disk" population is dominating over a possible old Milky Way-like stellar halo and that the SMC may be significantly larger than previously thought.