General CMB and Primordial Bispectrum Estimation I: Mode Expansion, Map-Making and Measures of f_NL

Understand

We present a detailed implementation of two bispectrum estimation methods which can be applied to general non-separable primordial and CMB bispectra.

• The method exploits bispectrum mode decompositions on the domain of allowed wavenumber or multipole values.
• Concrete mode examples constructed from symmetrised tetrahedral polynomials are given, demonstrating rapid convergence for known bispectra.
• We use these modes to generate simulated CMB maps of high resolution (l > 2000) given an arbitrary primordial power spectrum and bispectrum or an arbitrary late-time CMB angular power spectrum and bispectrum.