SELF-CALIBRATION OF GRAVITATIONAL SHEAR–GALAXY INTRINSIC ELLIPTICITY CORRELATION IN WEAK LENSING SURVEYS
SELF-CALIBRATION OF GRAVITATIONAL SHEAR–GALAXY INTRINSIC ELLIPTICITY CORRELATION IN WEAK LENSING SURVEYS
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DOI：
10.1088/0004-637x/720/2/1090
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发表时间：
2008-11
期刊：
影响因子：
--
通讯作者：
Pengjie Zhang
中科院分区：
文献类型：
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作者：
Pengjie Zhang
The galaxy intrinsic alignment is a severe challenge to precision cosmic shear measurement. We propose self-calibrating the induced gravitational shear–galaxy intrinsic ellipticity correlation (the GI correlation) in weak lensing surveys with photometric redshift measurements. (1) We propose a method to extract the intrinsic ellipticity–galaxy density cross-correlation (I–g) from the galaxy ellipticity–density measurement in the same redshift bin. (2) We also find a generic scaling relation to convert the extracted I–g correlation to the necessary GI correlation. We perform a concept study under simplified conditions and demonstrate its capability to significantly reduce GI contamination. We discuss the impact of various complexities on the two key ingredients of the self-calibration technique, namely the method for extracting the I–g correlation and the scaling relation between the I–g and the GI correlation. We expect that none of them will likely be able to completely invalidate the proposed self-calibration technique.
