Primordial Non-Gaussianities of inflationary step-like models

TL;DR

This study investigates non-Gaussian signatures in CMB maps generated by inflationary models with step-like potentials, revealing Gaussian deviations and compatibility with Planck data, thus linking inflationary features to observed non-Gaussianities.

Contribution

It demonstrates that step-like inflationary models can account for both the features in the power spectrum and the non-Gaussian signatures observed in CMB data, providing a unified explanation.

Findings

Detection of Gaussian deviations in simulated CMB maps.

Compatibility of non-Gaussianities with Planck observations.

Step-like models improve fit to CMB features.

Abstract

We use Minkowski Functionals to explore the presence of non-Gaussian signatures in simulated cosmic microwave background (CMB) maps. Precisely, we analyse the non-Gaussianities produced from the angular power spectra emerging from a class of inflationary models with a primordial step-like potential. This class of models are able to perform the best-fit of the low-$\ell$ `features', revealed first in the CMB angular power spectrum by the WMAP experiment and then confirmed by the Planck collaboration maps. Indeed, such models generate oscillatory features in the primordial power spectrum of scalar perturbations, that are then imprinted in the large scales of the CMB field. Interestingly, we discover Gaussian deviations in the CMB maps simulated from the power spectra produced by these models, as compared with Gaussian $\Lambda$CDM maps. Moreover, we also show that the kind and level of the non-Gaussianities produced in these simulated CMB maps are compatible with that found in the four foreground-cleaned Planck maps. Our results indicate that inflationary models with a step-like potential are not only able to improve the best-fit respect to the $\Lambda$CDM model accounting well for the `features' observed in the CMB angular power spectrum, but also suggesting a possible origin for certain non-Gaussian signatures observed in the Planck data.