A new weak lensing shear analysis method using ellipticity defined by 0th order moments

TL;DR

This paper introduces a novel weak lensing shear analysis method using ellipticity based on 0th order moments, which offers higher signal-to-noise ratio and comparable precision to traditional methods, confirmed through simulations and real data.

Contribution

The paper presents a new ellipticity measurement approach using 0th order moments for weak lensing, improving signal-to-noise ratio while maintaining accuracy.

Findings

0th-ellipticity correlates strongly with traditional ellipticity.

The method achieves similar precision to quadrupole-based ellipticity.

Application to Subaru data confirms effectiveness.

Abstract

We developed a new method that uses ellipticity defined by 0th order moments (0th-ellipticity) for weak gravitational lensing shear analysis. Although there is a strong correlation between the ellipticity calculated using this approach and the usual ellipticity defined by the 2nd order moment, the ellipticity calculated here has a higher signal-to-noise ratio because it is weighted to the central region of the image. These results were confirmed using data for Abell 1689 from the Subaru telescope. For shear analysis, we adopted the ellipticity of re-smeared artificial image (ERA) method for point spread function (PSF) correction, and we tested the precision of this 0th-ellipticity with simple simulation, then we obtained the same level of precision with the results of ellipticity defined by quadrupole moments. Thus, we can expect that weak lensing analysis using 0 shear will be improved in proportion to the statistical error.