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Abstract: We test the proposal by El-Zant et al that the dark matter density of haloscould be reduced through dynamical friction acting on heavy baryonic clumps inthe early stages of galaxy formation. Using N-body simulations, we confirm thatthe inner halo density cusp is flattened to 0.2 of the halo break radius by thesettling of a single clump of mass \ga 0.5% of the halo mass. We also find thatan ensemble of 50 clumps each having masses \ga 0.2% can flatten the cusp toalmost the halo break radius on a time scale of \sim9 Gyr, for an NFW halo ofconcentration 15. We summarize some of the difficulties that need to beovercome if this mechanism is to resolve the apparent conflict between theobserved inner densities of galaxy halos and the predictions of LCDM.

Author: J. R. Jardel, J. A. Sellwood Rutgers University

Source: https://arxiv.org/

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