Observable properties of the Dark Matter distribution

by Simon White (Max-Planck-Institut für Astrophysik, Garching)

Tuesday 16 Dec 2008, 16:45 → 18:15 Europe/Berlin

Hoersaal

There is hope that dark matter may soon be detected, either by observation of its annihilation products or in bolometer or resonant cavity experiments on Earth. The expected signals depend not only on the nature of dark matter, but also on the structure of its distribution. I will discuss the predictions of the concordance LambdaCDM cosmology on all relevant scales, including scales much smaller than those that can be simulated directly. Contrary to previous claims, such small-scale structure has almost no influence on the detectability of the predicted signals. Very small-scale clumps and dark matter caustics do not significantly enhance the detectability of annihilation radiation, nor do they cause the dark matter density seen by Earth-based experiments to deviate significantly from the large-scale mean in the Sun's vicinity. Dark matter streams are too weak and too abundant to be detected individually in such detectors, although residual structure in the dark matter energy distribution may provide some insight into the Milky Way's assembly history.