Astron. Astrophys. 358, L9-L12 (2000)

4. Conclusions

Counts of sources towards the Magellanic Clouds extracted from the DCMC (Cioni et al. 2000) allow differentiation in the (, I) colour-magnitude diagram into three groups of objects with different mean ages. The spatial distribution of the three age groups is quite different: in either Cloud, the youngest stars exhibit an irregular structure characterized by spiral arms and tidal features while the older stars are smoothly and regularly distributed. The distribution of younger stars is well-correlated with those of clusters, associations, HII regions and HI. The significant offset of the LMC Bar with respect to the overall circular disk suggests that the LMC potential is dominated by dark matter. The well-defined southern spiral arm may be due to tidal interaction with the SMC. The nature of the two northern spiral arms is uncertain. In the SMC, the regular, but double-peaked, structure of the AGB and RGB stars is remarkable, as is its offset from the HI distribution, and the mean age difference of the two maxima. Relatively faint east-west features in the younger star population (including the Wing) are probably also due to tidal interaction.

© European Southern Observatory (ESO) 2000

Online publication: June 26, 2000
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