A central degeneracy induced outer core in fermionic dark matter halos

Abstract: Several galaxy-scale observations challenge the predictions of the cold dark matter paradigm based on cosmological simulations. The cusp-core problem is one of the most outstanding. However, current simulations are unable to consider quantum statistical effects. For a fermionic dark matter halo, a degenerate inner core induces an extended outer core that dominates in gravity in the region relevant for rotation curve observation. We study the properties of this outer core and show that its density and radius are correlated. The prediction remarkably agrees with the measured scaling relation in both the slope and the magnitude. Such consistency suggests that the observed cored profiles do not contradict massive dark matter but indicate its fermionic nature.