Le 22 septembre 2017
De 10h30 à 12h00
Oliver Müller
University of Basel
Dwarf galaxies are tracers of the fine-structure of the large-scale structure of the universe, but their predicted distribution from simulations is in serious conflict with observations in the Local Group, the best studied group of galaxies today. Recently, a plane of satellites was discovered around Cen A, providing a unique opportunity to test cosmological predictions beyond the Local Group. We surveyed the complete Centaurus Group with the Dark Energy Camera, doubling the census of dwarf galaxies in the group. We found evidence that this satellite plane is corotating, posing a major challenge to LambdaCDM. Comparison to high-resolution dark matter simulations show that this finding is highly significant. Only recently another unexpected relation between the number of dwarf galaxies and the size of the bulge of the host galaxy was found. I present the newest results from our on going survey, targeting multiple nearby spiral galaxies and discuss the connection of this relation to the plane-of-satellite problem.