Constraining the primordial curvature perturbation using dark matter substructure

Understand

We investigate the primordial curvature perturbation by the observation of dark matter substructure.

• Assuming a bump in the spectrum of the curvature perturbation in the wavenumber of k>1 Mpc^{-1}, we track the evolution of the host halo and subhalos in a semi-analytic 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~10^3 Mpc^{-1}.