Signature of primordial non-Gaussianity on 21-cm power spectrum from dark ages

TL;DR

This paper investigates how primordial non-Gaussianity affects the 21-cm power spectrum during dark ages, showing its potential to provide tighter constraints than CMB measurements and the bispectrum.

Contribution

It provides a quantitative analysis of non-Gaussian effects on the 21-cm power spectrum and compares its constraining power to other methods.

Findings

21-cm power spectrum can constrain non-Gaussianity better than CMB measurements.

The 21-cm power spectrum has stronger constraining power than the bispectrum in most cases.

Ultimate potential of the 21-cm bispectrum surpasses that of the power spectrum.

Abstract

We study the signature of primordial non-Gaussianity imprinted on the power spectrum of the 21-cm line differential brightness temperature during dark ages. Employing the perturbative treatment of gravitational clustering, we quantitatively estimate the effects of the non-Gaussian and one-loop corrections on the 21-cm power spectrum. The potential impact of the use of the 21-cm power spectrum for the constraint on local-type primordial non-Gaussianity is investigated based on the Fisher matrix analysis. Our results show that the 21-cm power spectrum for an array with a baseline of several tens of kilometers can constrain the primordial non-Gaussianity to a level severer than that from cosmic microwave background measurements and its constraining power is stronger than that of the 21-cm bispectrum, while in the ultimate situation the 21-cm bispectrum eventually becomes more powerful.