APPROACHING THE CRAMER-RAO BOUND IN WEAK LENSING WITH PDF SYMMETRIZATION

doi:10.3847/1538-4357/834/1/8

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	APPROACHING THE CRAMER-RAO BOUND IN WEAK LENSING WITH PDF SYMMETRIZATION
	Zhang, Jun 2; Zhang, Pengjie 2; Luo, Wentao 1
刊名	ASTROPHYSICAL JOURNAL
	2017
卷号	834 期号:1
关键词	Gravitational Lensing: Weak Large-scale Structure Of Universe Methods: Data Analysis Techniques: Image Processing
ISSN号	0004-637X
DOI	10.3847/1538-4357/834/1/8
英文摘要	Weak lensing statistics is typically measured as the weighted sum of shear estimators or their products (shear-shear correlation). The weighting schemes are designed with a view to minimizing the statistical error without introducing systematic errors. It would be ideal to approach the Cramer-Rao bound (the lower bound of the statistical uncertainty) in shear statistics, though it is generally difficult to do so in practice. The reasons may include difficulties in galaxy shape measurement, inaccurate knowledge of the probability distribution function (PDF) of the shear estimator, misidentification of point sources as galaxies, etc. Using the shear estimators defined by Zhang et al., we show that one can overcome these problems, and allow shear measurement accuracy to approach the Cramer-Rao bound. This can be achieved by symmetrizing the PDF of the shear estimator, or the joint PDF of shear estimator pairs (for shear-shear correlation), without any prior knowledge of the PDF. Using simulated galaxy images, we demonstrate that under general observing conditions, this idea works as expected: it minimizes the statistical uncertainty without introducing systematic error.
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	IOP PUBLISHING LTD
WOS记录号	WOS:000391573000008
内容类型	期刊论文
源URL	[http://119.78.226.72/handle/331011/32661]
专题	中国科学院上海天文台
通讯作者	Zhang, Jun
作者单位	1.Shanghai Astron Observ, Key Lab Res Galaxies & Cosmol, Shanghai 200030, Peoples R China 2.Shanghai Jiao Tong Univ, Dept Phys & Astron, Shanghai 200240, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Jun,Zhang, Pengjie,Luo, Wentao. APPROACHING THE CRAMER-RAO BOUND IN WEAK LENSING WITH PDF SYMMETRIZATION[J]. ASTROPHYSICAL JOURNAL,2017,834(1).
APA	Zhang, Jun,Zhang, Pengjie,&Luo, Wentao.(2017).APPROACHING THE CRAMER-RAO BOUND IN WEAK LENSING WITH PDF SYMMETRIZATION.ASTROPHYSICAL JOURNAL,834(1).
MLA	Zhang, Jun,et al."APPROACHING THE CRAMER-RAO BOUND IN WEAK LENSING WITH PDF SYMMETRIZATION".ASTROPHYSICAL JOURNAL 834.1(2017).