Heidelberg Joint Astronomical Colloquium

Speaker Matthias Bartelmann
Title From Shape Measurement to Cluster Reconstruction: Some New Methods in Gravitational Lensing

Within the Cold Dark Matter paradigm for cosmogony, the internal structure of galaxy clusters can be precisely predicted. Numerical simulations quite unanimously agree on the mean density profile and the corrugation of the mass distribution by substructures. Are the predicted cluster properties in agreement with those found by measurement?

This question will set the theme of the talk. The talk is intended to pose questions more than to give answers. I shall begin outlining two new methods in gravitational lensing to improve our measurements of cluster mass distributions, continue by describing how unique mass reconstructions could be achieved including the physics of the thermal cluster plasma, and conclude by shedding doubt on the concept of cluster mass.

The presentation is layed-out to promote contributions and feedback by the audience.