Toward a Bias-free Selection Criterion in Shear Measurement

Sample selection is a necessary preparation for weak lensing measurement. It well-known that itself may introduce bias to the measured shear signal. Using image simulation and Fourier_Quad measurement pipeline, we quantify in various commonly used criteria (signal-to-noise ratio, magnitude, etc.). We propose new criterion defined power spectrum of galaxy image. This has low bias, it particularly convenient pipelines based on Fourier transformation.