Analytical noise bias correction for weak lensing shear analysis with ERA
Analytical noise bias correction for weak lensing shear analysis with ERA
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DOI：
10.1093/mnras/sty1746
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发表时间：
2018-02
影响因子：
4.8
通讯作者：
Y. Okura;T. Futamase
中科院分区：
文献类型：
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作者：
Y. Okura;T. Futamase
在统计弱引力透镜分析中，如宇宙剪切测量，需要高精度的弱引力透镜剪切测量来实现对宇宙学参数的严格约束。为此，背景星系的精确形状测量是绝对重要的，其中任何系统误差都应仔细校正。其中一个主要的系统误差来自于光子噪声，即来自大气通量的泊松噪声（噪声偏差）。本文在前人提出的ERA方法的框架内，研究了光子噪声对剪切测量的系统误差，并给出了一种实用的修正方法。对不同条件下的真实的星系图像进行了仿真实验，结果表明，该方法除对信噪比很低的星系外，对噪声偏差的校正均能达到80 ~ 90%。
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.