Weak Lensing Minima and Peaks: Cosmological Constraints and the Impact of Baryons

TL;DR

This paper introduces lensing minima as a new statistic for cosmological analysis in weak lensing data, demonstrating their robustness against baryonic effects and their complementarity to existing methods, leading to improved parameter constraints.

Contribution

The study presents lensing minima as a novel, non-Gaussian statistic for cosmology, evaluates baryonic impacts, and shows how combining minima with peaks enhances constraints.

Findings

Lensing minima are sensitive to non-Gaussian cosmological information.

Combining minima and peaks improves constraints by up to 63%.

Lensing minima are less affected by baryonic effects than peak counts.

Abstract

We present a novel statistic to extract cosmological information in weak lensing data: the lensing minima. We also investigate the effect of baryons on the cosmological constraints from peak and minimum counts. Using the \texttt{MassiveNuS} simulations, we find that lensing minima are sensitive to non-Gaussian cosmological information and are complementary to the lensing power spectrum and peak counts. For an LSST-like survey, we obtain $95\%$ credible intervals from a combination of lensing minima and peaks that are significantly stronger than from the power spectrum alone, by $44\%$, $11\%$, and $63\%$ for the neutrino mass sum $\sum m_\nu$, matter density $\Omega_m$, and amplitude of fluctuation $A_s$, respectively. We explore the effect of baryonic processes on lensing minima and peaks using the hydrodynamical simulations \texttt{BAHAMAS} and \texttt{Osato15}. We find that ignoring baryonic effects would lead to strong ($\approx 4 \sigma$) biases in inferences from peak counts, but negligible ($\approx 0.5 \sigma$) for minimum counts, suggesting lensing minima are a potentially more robust tool against baryonic effects. Finally, we demonstrate that the biases can in principle be mitigated without significantly degrading cosmological constraints when we model and marginalize the baryonic effects.