Fingerprints of anomalous primordial Universe on the abundance of large scale structures

Abstract

We study the predictions of anomalous inflationary models on the abundance of structures in large scale structure observations. The anomalous features encoded in primordial curvature perturbation power spectrum are (a): localized feature in momentum space, (b): hemispherical asymmetry and (c): statistical anisotropies. We present a model-independent expression relating the number density of structures to the changes in the matter density variance. Models with localized feature can alleviate the tension between observations and numerical simulations of cold dark matter structures on galactic scales as a possible solution to the missing satellite problem. In models with hemispherical asymmetry we show that the abundance of structures becomes asymmetric depending on the direction of observation to sky. In addition, we study the effects of scale-dependent dipole amplitude on the abundance of structures. Using the quasars data and adopting the power-law scaling knA-1 for the amplitude of dipole we find the upper bound nA < 0.6 for the spectral index of the dipole asymmetry. In all cases there is a critical mass scale Mc in which for M<Mc (M> Mc) the enhancement in variance induced from anomalous feature decreases (increases) the abundance of dark matter structures in Universe.