Dark matter haloes in the multicomponent model. III. From dwarfs to galaxy clusters

ABSTRACT A possibility of DM being multicomponent has a strong implication on resolving decades-long known cosmological problems on small scale. In addition to elastic scattering, the model allows for inelastic interactions, which can be characterized by a ‘velocity kick’ parameter. The simplest 2cDM model with cross-section $0.01\lesssim \sigma /m\lt 1\, \textrm {cm}^{2}{ \rm g}^{-1}$ and the kick velocity $V_{\mathrm{ k}}\simeq 100\, \rm {km\, s}^{-1}$ have been shown to robustly resolve the missing satellites, core-cusp, and too-big-to-fail problems in N-body cosmological simulations tested on Milky Way (MW)-like haloes of a virial mass ${\sim}5 \times 10^{11}\, {\rm M_{\odot }}$ (Papers I & II). With the aim of further constraining the parameter space available for the 2cDM model, we extend our analysis to dwarf and galaxy cluster haloes with their virial mass of ∼107−108 and ${\sim}10^{13} - 10^{14}\, {\rm M_{\odot }}$, respectively. We find that σ0/m ≳ 0.1 cm2g−1 is preferentially disfavoured for both dwarfs and galaxy cluster haloes in comparison with observations, while σ0/m = 0.001 cm2g−1 causes little perceptible difference from that of the CDM counterpart for most of the cross-section’s velocity dependence studied in this work. Our main result is that within the reasonable set of parameters, the 2cDM model can successfully explain the observational trends seen in dwarf galaxy and galaxy cluster haloes, and the model leaves us an open window for other possible alternative DM models.