Heymans and collaborators map dark matter
Catherine Heymans, at the January 2008 AAS meeting, showed a map of the dark matter in the supercluster of galaxies Abell 901/902. Since dark matter does not emit light, it must be detected by indirect means -- its effect on the light of distant galaxies behind the supercluster. By modelling this gravitional lensing of about 60,000 backgroud galaxies, Heymens was able to show that the dark matter in the supercluster concentrates in the same areas as the visible galaxies.