The connection between the cusp-to-core transformation and observational universalities of DM haloes

Abstract

Observations have revealed interesting universal properties of dark matter (DM) haloes especially around low-mass galaxies. Strigari et al. showed that DM haloes have common enclosed masses within 300 pc (Strigari relation). Kormendy & Freeman reported DM haloes having almost identical central surface densities (the μ0D relation). In addition, there exists a core-cusp problem, a discrepancy of the central density distribution between simulated haloes and observations. We investigate whether a scenario where cuspy haloes transform into cores by some dynamical processes can also explain their universal structural properties. It is shown that a cusp-to-core transformation model naturally reproduces the μ0D relation and that Strigari relation follows from the μ0D relation for dwarf galaxies. We also show that the central densities of cored dark haloes provide valuable information about their formation redshifts. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.