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OATS-DAUT SEMINAR
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Speaker: Giuseppe Bono (INAF-Osservatorio Astronomico di Roma)

Title: Omega Centauri: the possible link between globular clusters and dwarf galaxies

Date: Wednesday, February 28th, 2007
Time: 12:00 noon
Venue: Villa Bazzoni

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Abstract: Omega Centauri is one of the most interesting and puzzling Galactic stellar system. According to several empirical evidence (kinematics, total mass, spread in chemical composition) this system has been considered the relic of a dwarf spheroidal galaxy. However, the mass-to-light ratio and the velocity dispersion are quite typical of Galactic globular clusters. We present new star counts of evolved stellar tracers in Omega Centauri based on deep (ACS@HST) and wide (WFI@2.2m ESO/MPI) multiband photometric investigations. In particular, we compare observed star counts with evolutionary lifetimes predicted by canonical and He-enriched stellar structures. Finally, we briefly mention a few extragalactic implications of He-enriched stellar populations.
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