Structure formation under inelastic two-component dark matter: halo statistics and matter power spectra in the high- <i>z</i>  universe

ABSTRACT We present hydrodynamic simulations of a flavour-mixed two-component dark matter (2cDM) model that utilize IllustrisTNG baryonic physics. The model parameters are explored for two sets of power laws of the velocity-dependent cross-sections, favoured on the basis of previous studies. The model is shown to suppress the formation of structures at scales $k\gtrsim 10^2\ h\text{ Mpc}^{-1}$ up to 40 per cent compared to cold dark matter at redshifts $z\sim 5{-}2$. We compare our results to structure enhancement and suppression due to cosmological and astrophysical parameters presented in the literature and find that 2cDM effects remain relevant at galactic and subgalactic scales. The results indicate the robustness of the role of non-gravitational dark matter interactions in structure formation and the absence of putative degeneracies introduced by baryonic feedback at high z. The predictions made can be further tested with future Ly $\alpha$ forest observations.