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

¹ National Astronomical Observatory of Japan, 181-8588 Tokyo, Japan
e-mail: yuki.okura@nao.ac.jp
² Astronomical Institute, Tohoku University, 980-8578 Sendai, Japan
e-mail: tof@astr.tohoku.ac.jp

Received: 2 December 2014
Accepted: 10 February 2015

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 method for point spread function 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.