Stage IV baryonic feedback correction for non-Gaussianity inference

Monthly Notices of the Royal Astronomical Society, vol. 536, pp. 2064–2071

Abstract

ABSTRACT Non-Gaussian statistics of the projected weak lensing field are powerful estimators that can outperform the constraining power of the two-point functions in inferring cosmological parameters. This is because these estimators extract the non-Gaussian information contained in the small scales. However, fully leveraging the statistical precision of such estimators is hampered by theoretical uncertainties, such as those arising from baryonic physics. Moreover, as non-Gaussian estimators mix different scales, there exists no natural cut-off scale below which baryonic feedback can be completely removed. We therefore present a Bayesian solution for accounting for baryonic feedback uncertainty in weak lensing non-Gaussianity inference. Our solution implements Bayesian model averaging (BMA), a statistical framework that accounts for model uncertainty and combines the strengths of different models to produce more robust and reliable parameter inferences. We demonstrate the effectiveness of this approach in a Stage IV convergence peak count analysis, including three baryonic feedback models. We find that the resulting BMA posterior distribution safeguards parameter inference against biases due to baryonic feedback, and therefore provides a robust framework for obtaining accurate cosmological constraints at Stage IV precision under model uncertainty scenarios.

Authors 2

1. Daniela Grandón corresponding Aachen Mathematical Institute

   Leiden University

   Affiliation as printed

   Mathematical Institute, Leiden University , Gorlaeus Building, Einsteinweg 55, NL-2333 CC Leiden ,

   Mathematical Institute, Leiden University , Snellius Gebouw, Niels Bohrweg 1, NL-2333 CA Leiden,

2. Elena Sellentin Aachen Leiden Observatory Mathematical Institute

   Leiden University · Leiden Observatory

   Affiliation as printed

   Leiden Observatory, Leiden University , Gorlaeus Building, Einsteinweg 55, NL-2333 CC Leiden ,

   Mathematical Institute, Leiden University , Gorlaeus Building, Einsteinweg 55, NL-2333 CC Leiden ,

   Leiden Observatory, Leiden University , Oort Gebouw, Niels Bohrweg 2, NL-2333 CA Leiden,

   Mathematical Institute, Leiden University , Snellius Gebouw, Niels Bohrweg 1, NL-2333 CA Leiden,