Detecting bispectral acoustic oscillations from inflation using a new flexible estimator

Abstract

We present a new flexible estimator for comparing theoretical templates for the predicted bispectrum of the cosmic microwave background (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 f NL is sufficiently large. The character and statistical weight of the acoustic oscillations and the decay tail are described in detail. © 2010 The Authors. Journal compilation. © 2010 RAS.