High-resolution CMB bispectrum estimator with flexible modal basis

TL;DR

This paper introduces a new high-resolution CMB bispectrum estimator combining existing methods, optimized for computational efficiency, validated against Planck data, and capable of constraining complex primordial non-Gaussianity models.

Contribution

The paper presents a novel pipeline that integrates KSW and Modal estimators with advanced numerical techniques, enabling analysis of complex bispectrum shapes with improved accuracy and efficiency.

Findings

Validated pipeline against Planck data

Constrained oscillatory non-Gaussian models

No significant primordial non-Gaussianity detected

Abstract

We present a new independent pipeline for the CMB bispectrum estimation of primordial non-Gaussianity and release a public code for constraining bispectrum shapes of interest based on the Planck 2018 temperature and polarization data. The estimator combines the strengths of the conventional KSW and Modal estimators at the cost of increased computational complexity, which has been made manageable through intensive algorithmic and implementation optimization. We also detail some methodological advances in numerical integration over a tetrapyd - domain where the bispectrum is defined on - via new quadrature rules. The pipeline has been validated both internally and against Planck. As a proof-of-concept example, we constrain some highly oscillatory models that were out of reach in conventional analyses using a targeted basis with a fixed oscillation frequency, and no significant evidence for primordial non-Gaussianity of these shapes is found. The methodology and code developed in this work will be directly applicable to future surveys where we expect a notable boost in sensitivity.