Scale and shape dependent non-Gaussianity in the presence of inflationary vector fields

Understand

We consider cosmological inflationary models in which vector fields play some role in the generation of the primordial curvature perturbation $\zeta$.

• Such models are interesting because the involved vector fields naturally seed statistical anisotropy in the primordial fluctuations which could eventually leave a measurable imprint on the cosmic microwave background fluctuations.
• In this article, we estimate the scale and shape dependent effects on the non-Gaussianity (NG) parameters due to the scale dependent statistical anisotropy in the distribution of the fluctuations.
• For concreteness, we use a power spectrum (PS) of the fluctuations of the quadrupolar form: $P_\zeta(\vec{k})\equiv P_\zeta(k)[1+g_\zeta(k)(\hat{n} \cdot \hat{k})^2 ]$, where $g_{\zeta}(k)$ is the only quantity which parametrizes the level of statistical anisotropy and $\hat{n}$ is a unitary vector which points towards the preferred direction.