Constraining the primordial curvature perturbation using dark matter substructure

We investigate the primordial curvature perturbation by the observation of the dark matter substructure. Assuming a bump in the spectrum of the curvature perturbation in the wave number of k >1 Mpc^-1, we track the evolution of the host halo and subhalos in a semianalytic way. Taking into account possible uncertainties in the evaluation of the tidal stripping effect on the subhalo growth, we find a new robust bound on the curvature perturbation with a bump from the number of observed dwarf spheroidal galaxies in our Galaxy and the observations of the stellar stream. The upper limit on the amplitude of the bump is O(10^-7) for k ∼103 Mpc^-1. Furthermore, we find the boost factor, which is crucial for the indirect detection of dark matter signals, is up to O(10⁴) due to the bump that is allowed in the current observational bounds.