Anisotropic non-Gaussianity from vector field perturbations

TL;DR

This paper investigates how vector field perturbations can induce anisotropic non-Gaussianity in primordial curvature perturbations, with potential observability in cosmological data.

Contribution

It provides a calculation of the anisotropic non-Gaussianity parameter fNL in both curvaton and end-of-inflation scenarios, highlighting its potential detectability.

Findings

Anisotropic non-Gaussianity parameter fNL can be significant.

Observable anisotropy in primordial perturbations is possible.

Calculations apply to both curvaton and end-of-inflation models.

Abstract

We suppose that a vector field perturbation causes part of the primordial curvature perturbation. The non-Gaussianity parameter fNL is then, in general, statistically anisotropic. We calculate its form and magnitude in the curvaton scenario and in the end-of-inflation scenario. We show that this anisotropy could easily be observable.