Detecting Bispectral Acoustic Oscillations from Inflation Using a New Flexible Estimator

TL;DR

This paper introduces a new flexible estimator for analyzing the bispectrum of CMB anisotropies, capable of detecting acoustic oscillations and features in future Planck data, especially for large fNL values.

Contribution

A novel binning-based estimator that improves detection of bispectral features and acoustic oscillations in CMB data, adaptable to foreground masking and specific bispectrum shapes.

Findings

Estimator can detect acoustic oscillations in bispectrum

Effective for large fNL in future Planck data

Provides detailed characterization of bispectral features

Abstract

We present a new flexible estimator for comparing theoretical templates for the predicted bispectrum of the CMB anisotropy to observations. This estimator, based on binning in harmonic space, generalizes the optimal estimator of Komatsu, Spergel, and Wandelt by allowing an adjustable weighting scheme for masking possible foreground and other contaminants and detecting particular noteworthy features in the bispectrum. The utility of this estimator is illustrated by demonstrating how acoustic oscillations in the bispectrum and other details of the bispectral shape could be detected in the future PLANCK data provided that fNL is sufficiently large. The character and statistical weight of the acoustic oscillations and the decay tail are described in detail.