Cosmological constraints from the convergence 1-point probability distribution

TL;DR

This paper demonstrates that the convergence 1-point PDF in weak lensing provides competitive cosmological constraints, can break parameter degeneracies, and enhances analysis robustness when combined with shear measurements.

Contribution

It introduces a Fisher analysis using the convergence PDF from fast simulations, showing its effectiveness and synergy with shear data for cosmological parameter estimation.

Findings

Convergence PDF yields competitive constraints on _m and _8.

Combining PDF with shear reduces systematic impacts and improves figure of merit.

A correction factor for unbiased Fisher information from limited simulations is proposed.

Abstract

We examine the cosmological information available from the 1-point probability distribution (PDF) of the weak-lensing convergence field, utilizing fast L-PICOLA simulations and a Fisher analysis. We find competitive constraints in the $\Omega_m$-$\sigma_8$ plane from the convergence PDF with $188\ arcmin^2$ pixels compared to the cosmic shear power spectrum with an equivalent number of modes ($\ell < 886$). The convergence PDF also partially breaks the degeneracy cosmic shear exhibits in that parameter space. A joint analysis of the convergence PDF and shear 2-point function also reduces the impact of shape measurement systematics, to which the PDF is less susceptible, and improves the total figure of merit by a factor of $2-3$, depending on the level of systematics. Finally, we present a correction factor necessary for calculating the unbiased Fisher information from finite differences using a limited number of cosmological simulations.