We perform a study of the nonlinear clustering of matter in the late-forming dark matter (LFDM) scenario in which dark matter results from the transition of a nonminimally coupled scalar field from radiation to collisionless matter. A distinct feature of this model is the presence of a damped oscillatory cutoff in the linear matter power spectrum at small scales. We use a suite of high-resolution N-body simulations to study the imprints of LFDM on the nonlinear matter power spectrum, the halo mass and velocity functions and the halo density profiles. The model largely satisfies high-redshift matter power spectrum constraints from Lyman-$\alpha$ forest measurements, while it predicts suppressed abundance of low-mass halos ($\sim {10}^9–{10}^{10}{\mathrm{h}}^{-1}{\mathrm{M}}_{\odot }$) at all redshifts compared to a vanilla $\mathrm{\Lambda }\mathrm{CDM}$ model. The analysis of the LFDM halo velocity function shows a better agreement than the $\mathrm{\Lambda }\mathrm{CDM}$ prediction with the observed abundance of low-velocity galaxies in the local volume. Halos with mass $M\gtrsim {10}^{11}{\mathrm{h}}^{-1}{\mathrm{M}}_{\odot }$ show minor departures of the density profiles from $\mathrm{\Lambda }\mathrm{CDM}$ expectations, while smaller-mass halos are less dense, consistent with the fact that they form later than their $\mathrm{\Lambda }\mathrm{CDM}$ counterparts.

• Received 5 December 2014

DOI:https://doi.org/10.1103/PhysRevD.92.063502