Cosmological Parameter Biases from Doppler-Shifted Weak Lensing in Stage IV Experiments

TL;DR

This paper evaluates the impact of Doppler-shift effects on weak lensing measurements in Stage IV surveys, finding that neglecting this correction introduces negligible bias in cosmological parameters.

Contribution

It provides the first quantitative assessment of Doppler-shift biases in Stage IV weak lensing surveys using Fisher matrix analysis.

Findings

Doppler-shift effects can be safely neglected in Stage IV weak lensing analyses.

The study offers publicly available code for bias assessment.

Neglecting Doppler-shift does not significantly bias cosmological parameters.

Abstract

The advent of Stage IV weak lensing surveys will open up a new era in precision cosmology. These experiments will offer more than an order-of-magnitude leap in precision over existing surveys, and we must ensure that the accuracy of our theory matches this. Accordingly, it is necessary to explicitly evaluate the impact of the theoretical assumptions made in current analyses on upcoming surveys. One effect typically neglected in present analyses is the Doppler-shift of the measured source comoving distances. Using Fisher matrices, we calculate the biases on the cosmological parameter values inferred from a Euclid-like survey, if the correction for this Doppler-shift is omitted. We find that this Doppler-shift can be safely neglected for Stage IV surveys. The code used in this investigation is made publicly available.