Le 8 février 2013
À 10h30
Salle de Cours – Grande Coupole
Michelle COLLINS
MPIA Heidelberg, Allemagne
Over the past few years, we have been conducting a systematic survey of the dwarf spheroidal galaxies of M31 using the Keck II DEIMOS spectrograph as part of the Pan Andromeda Archaeological Survey (PAndAS) project. This has allowed our group to measure systemic velocities, central masses and average metallicities for 20 of the 28 M31 dSphs. I will present this homogeneous dataset, and highlight some of our more unusual findings, including the curiously low mass objects, Andromeda’s XIX, XXI and XXV. I will discuss the significance of this result for the current cosmological paradigm, and what physical processes – such as feedback and tidal stripping – could have caused the unexpectedly low densities of the dark matter halos for these objects.