Optimal estimator for the amplitude of the bispectrum from IR sources

TL;DR

This paper introduces a fast, optimal estimator for the IR sources bispectrum amplitude, accounting for partial sky coverage and noise, and explores its detection prospects and joint analysis with other non-Gaussian signals.

Contribution

The paper presents a novel estimator for IR bispectrum amplitude that handles realistic observational conditions and demonstrates its application for joint non-Gaussianity constraints.

Findings

IR bispectrum detection is unlikely below 220 GHz with Planck-like data

Detection at or above 220 GHz is feasible if CMB is removed

Radio and IR non-Gaussianity estimations are strongly coupled

Abstract

We devise a fast and optimal estimator for the amplitude of the bispectrum of clustered Infrared (IR) point-sources. We show how this estimator can account for the cases of partial sky coverage and inhomogeneous noise. Expected detection significance are presented in terms of signal-to-noise, finding that the IR bispectrum will realistically be undetectable below 220 GHz with a Planck-like experiment; on the contrary detection may be achieved at, or above, 220 GHz especially if the CMB is removed. We also show how this estimator can be combined with estimators of radio and CMB non-Gaussianity to build up joint robust constraints. On the one hand, we find that, for a Planck-like experiment, CMB non-Gaussianity estimation can be decoupled from point-source contributions, unless few sources are masked. On the other hand, we find that the estimation of radio and IR non-Gaussianity are strongly coupled, which diminishes their separate detection significance.