29 September 2005
29 September 2005
Speaker: Gary Da Costa (Mt. Stromlo Observatory, The Australian National Observatory)
Title:
The Structure of the Sculptor and Fornax Dwarf Spheroidal Galaxies
Abstract:
The dwarf Spheroidal (dSph) companion galaxies to the
Milky Way are generally accepted as among the 'darkest' galaxies
known, with mass-to-light ratios exceeding 100 or more in some
cases. The alternative to the high M/L ratios is that the
dSphs are not in virial equilibrium, but are instead undergoing tidal
disruption by the Milky Way. We have used wide field imaging to
investigate the outer structure of two southern dSphs in order to
constrain their level of interaction with the Galaxy. For
Sculptor, we find little evidence for any such interaction. The
outer structure of Fornax, however, is surprisingly complex though
we argue that this is not the result of gravitational interaction
with the Milky Way.
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