Dark matter caustics and the enhancement of self-annihilation flux

Abstract

Cold dark matter haloes are populated by caustics, which are yet to be resolved in N-body simulations or observed in the Universe. Secondary infall model provides a paradigm for the study of caustics in "typical" haloes assuming that they have had no major mergers and have grown only by smooth accretion. This is a particular characteristic of the smallest dark matter haloes of about 10^{-5} Mo, which although "atypical" contain no substructures and could have survived until now with no major mergers. Thus using this model as the first guidline, we evaluate the neutralino self-annihilation flux for these haloes. Our results show that caustics could leave a distinct sawteeth signature on the differential and cumulative fluxes coming from the outer regions of these haloes. The total annihilation signal from the regions away from the centre can be boosted by about forty percents.

arXiv commentTo appear in JCAP, 4 pages, 3 figures

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• Density Profiles of CDM Microhalos and their Implications for Annihilation Boost Factors
• The Caustic Ring Model of the Milky Way Halo
• Caustics in growing Cold Dark Matter Haloes
• A further look at particle annihilation in dark matter caustics
• Seen and unseen tidal caustics in the Andromeda galaxy
• WIMP annihilation in caustics
• Resolving infall caustics in dark matter halos
• Self-Similar Shocks and Winds in Galaxy Clusters
• Caustics, cold flows, and annual modulation
• Testing universal dark-matter caustic rings with galactic rotation curves