Cold Dark Matter Caustics

By Pierre Sikivie, University of Florida

The late infall of cold dark matter onto an isolated galaxy, such as the Milky Way, produces discrete flows throughout its halo, and associated caustics. In particular, there is a set of 'caustic rings' in or near the galactic plane. Caustic rings are closed tubes whose cross-section is an elliptic umbilic catastrophe. I'll argue on theoretical and observational grounds that the caustic ring radii a_n (n=1,2 ..) obey the approximate law: a,sub>n ∼ 1/n. This has important implications for dark matter searches.