Signature of Primordial Non-Gaussianity on Matter Power Spectrum

TL;DR

This paper investigates how primordial non-Gaussianity influences the matter and galaxy power spectra through gravitational clustering, highlighting the effects of different non-Gaussian types on cosmological parameter estimation.

Contribution

It provides a quantitative analysis of primordial non-Gaussian effects on power spectra using perturbation theory and explores their implications for galaxy bias and cosmological measurements.

Findings

Local-type non-Gaussianity induces scale-dependent bias in galaxy power spectra.

Equilateral-type non-Gaussianity does not cause scale-dependent bias.

Primordial non-Gaussianity can affect cosmological parameter estimation.

Abstract

Employing the perturbative treatment of gravitational clustering, we discuss possible effects of primordial non-Gaussianity on the matter power spectrum. As gravitational clustering develops, the coupling between different Fourier modes of density perturbations becomes important and the primordial non-Gaussianity which intrinsically possesses a non-trivial mode-correlation can affect the late-time evolution of the power spectrum. We quantitatively estimate the non-Gaussian effect on power spectrum from the perturbation theory. The potential impact on the cosmological parameter estimation using the power spectrum are investigated based on the Fisher-matrix formalism. In addition, on the basis of the local biasing prescription, non-Gaussian effects on the galaxy power spectrum are considered, showing that the scale-dependent biasing arises from a local-type primordial non-Gaussianity. On the other hand, an equilateral-type non-Gaussianity does not induce such scale-dependence because of weaker mode-correlations between small and large Fourier modes.