Analytical Noise Bias Correction for Weak Lensing Shear Analysis with ERA

TL;DR

This paper presents a practical correction method for photon noise bias in weak lensing shear measurements using the ERA technique, significantly improving measurement accuracy in simulated galaxy images.

Contribution

It introduces an analytical noise bias correction method tailored for the ERA shear measurement framework, validated through simulations.

Findings

Corrects 80-90% of noise bias in simulations

Effective for galaxies with moderate to high signal-to-noise ratios

Reduces systematic errors in weak lensing shear analysis

Abstract

Highly precise weak lensing shear measurement is required for statistical weak gravitational lensing analysis such as cosmic shear measurement to achieve severe constraint on the cosmological parameters. For this purpose, the accurate shape measurement of background galaxies is absolutely important in which any systematic error in the measurement should be carefully corrected. One of the main systematic error comes from photon noise which is Poisson noise of flux from the atmosphere(noise bias). We investigate how the photon noise makes a systematic error in shear measurement within the framework of ERA method we developed in earlier papers and gives a practical correction method. The method is tested by simulations with real galaxy images with various conditions and it is confirmed that it can correct $80 \sim 90\%$ of the noise bias except for galaxies with very low signal to noise ratio.