Self-Interacting Dark Matter and the Distribution of Matter in Clusters of Galaxies
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概要
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We study the formation of dark halos in a universe dominated by Cold Dark Matter with a positive cosmological constant under the assumption that Cold Dark Matter particles have a finite cross-section for elastic collisions. We compare the evolution when dark matter mean free path is comparable to halo sizes, with the collisionless and "fluid" limit. We show that a few collisions per particle per Hubble time at halo centre can substantially affect the central density profile. An order of magnitude larger cross-sections cause sufficient relaxation for massive clusters to develop large cores. Ray-tracing simulations of gravitational lensing show that giant arcs as seen in many clusters can only be produced if dark matter collisions are very rare. We conclude that the scattering cross-section in clusters must be very small, below〜10^<-25>cm 〓Gev, to be compatible with the observed ability of clusters to produce both radial and tangential arcs.
- 素粒子論グループ 素粒子研究編集部の論文
- 2001-07-20