Constraints on τNL from Planck temperature and polarization

We update constraints on the amplitude of the primordial trispectrum, using the final Planck mission temperature and polarization data. In the squeezed limit, a cosmological local trispectrum would be observed as a spatial modulation of small-scale power on the CMB sky. We reconstruct this signal as a source of statistical anisotropy via quadratic estimator techniques. We systematically demonstrate how the estimated power spectrum of a reconstructed modulation field can be translated into a constraint on tau(NL) via likelihood methods, demonstrating the procedures effectiveness by inferring known tau(NL) signal(s) from simulations. Our baseline results constrain tau(NL) < 1700 at the 95% confidence level, providing the most stringent constraints to date.

Automated summary

This study updates constraints on the amplitude of the primordial trispectrum using final Planck mission data, reconstructing a spatial modulation signal for a cosmological local trispectrum and translating the estimated power spectrum into a constraint on tau(NL) via likelihood methods. The research provides the most stringent constraints to date by inferring known tau(NL) signals from simulations.