Cosmic Infrared Background anisotropies as a window into primordial non-Gaussianity

TL;DR

This paper explores how measurements of the cosmic infrared background's anisotropies can serve as a sensitive probe for primordial non-Gaussianity, especially the local bispectrum shape, using future space mission data.

Contribution

It demonstrates that with sufficient frequency channels, CIB measurements can detect local primordial non-Gaussianity with |f_nl| < 1, overcoming galactic dust contamination.

Findings

CIB power spectrum is sensitive to primordial non-Gaussianity.

Dust contamination can be mitigated with multi-frequency data.

Future space missions can probe f_nl < 1.

Abstract

The angular power spectrum of the cosmic infrared background (CIB) is a sensitive probe of the local primordial bispectrum. CIB measurements are integrated over a large volume so that the scale dependent bias from the primordial non-Gaussianity leaves a strong signal in the CIB power spectrum. Although galactic dust dominates over the non-Gaussian CIB signal, it is possible to mitigate the dust contamination with enough frequency channels, especially if high frequencies such as the Planck 857 GHz channel are available. We show that, in this case, measurements of the cosmic microwave background from future space missions should be able to probe the local bispectrum shape down to an amplitude |f_nl| < 1.