# Quantifying systematics from the shear inversion on weak-lensing peak counts

## TL;DR

This paper investigates how neglecting the convergence-shear inversion in weak-lensing peak counts introduces biases in cosmological parameter estimation, emphasizing the need for accurate modeling in future high-precision surveys.

## Contribution

It quantifies the bias caused by ignoring the shear inversion in weak-lensing peak models and highlights its impact on cosmological constraints, especially on dark energy parameters.

## Key findings

- Neglecting shear inversion causes a small but significant bias.
- Bias depends on the parameter Sigma_8.
- Bias can lead to 2-sigma differences in dark energy constraints.

## Abstract

Weak-lensing peak counts provide a straightforward way to constrain cosmology by linking local maxima of the lensing signal to the mass function. Recent applications to data have already been numerous and fruitful. However, the importance of understanding and dealing with systematics increases as data quality reaches an unprecedented level. One of the sources of systematics is the convergence-shear inversion. This effect, inevitable when carrying out a convergence field from observations, is usually neglected by theoretical peak models. Thus, it could have an impact on cosmological results. In this paper, we study the bias from neglecting (mis-modeling) the inversion. Our tests show a small but non-negligible bias. The cosmological dependence of this bias seems to be related to the parameter Sigma_8. When this bias propagates to the parameter estimation, we discovered that constraint contours involving the dark energy equation of state can differ by 2-sigma. Such an effect can be even larger for future high-precision surveys and we argue that the inversion should be properly modeled for theoretical peak models.