Surface brightness profiles and structural parameters for 10 rich stellar clusters in the Small Magellanic Cloud

As a follow-up to our recent study of a large sample of Large Magellanic Cloud (LMC) clusters, we have conducted a similar study of the structures of 10 Small Magellanic Cloud (SMC) clusters, using archival Hubble Space Telescope snapshot data. We present surface brightness profiles for each cluster and derive structural parameters, including core radii and luminosity and mass estimates, using exactly the same procedure as for the LMC sample. Because of the small sample size, the SMC results are not as detailed as for the larger LMC sample. We do not observe any post-core-collapse clusters (although we did not expect to), and there is little evidence for any double clusters in our sample. None the less, despite the small sample size, we show for the first time that the SMC clusters follow almost exactly the same trend in core radius with age observed for the LMC system, including the apparent bifurcation at several hundred Myr. This further strengthens our argument that this relationship represents true physical evolution in these clusters, with some developing significantly expanded cores due to an as yet unidentified physical process. Additional data, both observational and from N-body simulations, are still required to clarify many issues.