The systematic error test for PSF correction in weak gravitational lensing shear measurement by The ERA Method by Idealizing PSF

TL;DR

This paper introduces an improved ERA method for PSF correction in weak lensing shear measurement, enabling accurate correction with minimal assumptions and demonstrating less than 0.1% systematic error in tests and real data.

Contribution

The paper presents a novel ERA method that corrects PSF effects in weak lensing without approximations, handling realistic galaxy and PSF shapes.

Findings

Systematic error less than 0.1% in numerical tests

Effective correction of complex PSF and galaxy shapes

Fast processing time per object (under 1 second)

Abstract

We improve the ERA(Ellipticity of Re-smeared Artificial image) method of PSF(Point Spread Function) correction in weak lensing shear analysis in order to treat realistic shape of galaxies and PSF. This is done by re-smearing PSF and the observed galaxy image smeared by a RSF(Re-Smearing Function), and allows us to use a new PSF with a simple shape and to correct PSF effect without any approximations and assumptions. We perform numerical test to show that the method applied for galaxies and PSF with some complicated shapes can correct PSF effect with systematic error less than 0.1%. We also apply ERA method for real data of Abell 1689 cluster to confirm that it is able to detect the systematic weak lensing shear pattern. The ERA method requires less than 0.1 or 1 second to correct PSF for each object in numerical test and real data analysis, respectively.