Abstract

Contributed Talk - Splinter LargeScale

Thursday, 10 September 2026, 17:00   (MW-2235)

Going below and beyond: improving systematics control in cosmological surveys using one-point statistics

Carolyn Mill, Lina Castiblanco, Cora Uhlemann
Newcastle University

Weak gravitational lensing is one of the most powerful probes of cosmic structure and dark energy, but its constraining power is fundamentally limited by systematic effects, particularly photometric redshift uncertainties and intrinsic alignment contamination, whose interplay can bias inferred cosmological parameters. While the shear two-point function (or power spectrum) remains the workhorse statistic for weak lensing, it captures only Gaussian information and discards the non-Gaussian signal generated by nonlinear structure growth at late times. In this work, we present a joint analysis combining the weak lensing power spectrum with the one-point probability distribution function (PDF) of the convergence field. The convergence PDF is sensitive to non-Gaussian information not captured by two-point statistics, and we show that combining it with the power spectrum significantly improves constraints on both cosmological parameters and the systematic parameters governing intrinsic alignments and photometric redshift errors. We quantify the improvement in constraining power from this 1-point/2-point combination and discuss its implications for forthcoming analyses with Euclid and LSST, where controlling systematics will be essential to fully exploit the statistical power of these surveys.