Caustic ring singularity
- Department of Physics, University of Florida, Gainesville, Florida 32611 (United States)
I investigate the caustics produced by the fall of collisionless dark matter in and out of a galaxy in the limit of negligible velocity dispersion. The outer caustics are spherical shells enveloping the galaxy. The inner caustics are rings. These are located near where the particles with the most angular momentum are at their distance of closest approach to the galactic center. The surface of a caustic ring is a closed tube whose cross section is a D[sub [minus]4] catastrophe. It has three cusps amongst which exists a discrete Z[sub 3] symmetry. A detailed analysis is given in the limit where the flow of particles is axially and reflection symmetric and where the transverse dimensions of the ring are small compared to the ring radius. Five parameters describe the caustic in that limit. The relations between these parameters and the initial velocity distribution of the particles are derived. The structure of the caustic ring is used to predict the shape of the bump produced in a galactic rotation curve by a caustic ring lying in the galactic plane. [copyright] [ital 1999] [ital The American Physical Society]
- OSTI ID:
- 6470936
- Journal Information:
- Physical Review, D, Vol. 60:6; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
Similar Records
Inner caustics of cold dark matter halos
Caustic ring model of the Milky Way halo