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OATS-DAUT SEMINAR
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Speaker:
Gary Mamon (Institut d'Astrophysique de Paris)
Title:
Kinematical and dynamical modelling of elliptical galaxies
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Abstract:
While spiral galaxies have easily measurable rotation curves, whose flat
shapes are best explained by dark matter halos, it is much more difficult
to measure the presence of dark matter around elliptical galaxies. Much
excitement was generated from the analysis of Romanowsky et al. (Science,
2003) who measured low velocity dispersions for planetary nebulae around
selected nearby giant ellipticals, especially because their kineamtical
modelling of their observations led them to conclude to a strong lack of
dark matter around these ellipticals.
After a long review of how to extract the mass profiles from spectroscopic
observations of the internal kinematics of spherical systems, I will
describe an analysis (recently published in Nature) of the elliptical-like
galaxies, produced in detailed simulations of major mergers of realistic
spiral galaxies. The merger remnants indeed look very much like elliptical
galaxies, and I will describe and explain the discrepancy with the result
reported in Science.
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