The Komatsu Spergel Wandelt estimator for oscillations in the cosmic microwave background bispectrum

TL;DR

This paper introduces a flexible estimator for detecting oscillating signals in the cosmic microwave background bispectrum, enabling analysis across a wide range of frequencies to improve understanding of inflationary models.

Contribution

It presents the Komatsu Spergel Wandelt (KSW) estimator for oscillations in the CMB bispectrum, capable of analyzing arbitrary frequencies for separable shapes, enhancing prior methods.

Findings

The estimator can determine amplitude, phase, and frequency with high precision.

It provides insights into the 3-point function in real space.

The method extends analysis capabilities beyond previous frequency limitations.

Abstract

Oscillating shapes of the primordial bispectrum are present in many inflationary models. The Planck experiment has recently published measurements of oscillating shapes, which were however limited to the efficient frequency range of the used analysis method. Here we study the KSW estimator for oscillations in the CMB bispectrum, that allows to examine arbitrary oscillation frequencies for separable oscillating bispectrum shapes. We study the precision with which amplitude, phase and frequency can be determined with our estimator. An examination of the 3-point function in real space gives further insight into the estimator.