期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 388, 期 3, 页码 991-1000出版社
OXFORD UNIV PRESS
DOI: 10.1111/j.1365-2966.2008.13478.x
关键词
gravitational lensing; cosmology : theory; large-scale structure of Universe
资金
- Humboldt Foundation
- European Commission Programme [MOIF-CT-2006-21891]
- NSERC
- CIAR
- RTN Network DUEL
- DFG through the TR33 'The Dark Universe'
- [SCHN 342/6-1]
We investigate the impact of the observed correlation between a galaxy's shape and its surrounding density field on the measurement of third-order weak lensing shear statistics. Using numerical simulations, we estimate the systematic error contribution to a measurement of the third-order moment of the aperture mass statistic (GGG) from three-point intrinsic ellipticity correlations (III), and the three-point Coupling between the weak lensing, shear experienced by distant galaxies and the shape of foreground galaxies (GGI and GII). We find that third-order weak lensing statistics are typically more strongly contaminated by these physical systematics compared to second-order shear measurements, contaminating the measured three-point signal for moderately deep surveys with a median redshift z(m) similar to 0.7 by similar to 15 per cent. It has been shown that accurate photometric redshifts will be Crucial to correct for this effect, once a model and the redshift dependence of the effect can be accurately constrained. To this end we provide redshift-dependent fitting functions to our results and propose a new tool for the observational study of intrinsic galaxy alignments. For a shallow survey with z(m) similar to 0.4 we find III to be an order of magnitude larger than the expected cosmological GGG shear signal. Compared to the two-point intrinsic ellipticity correlation which is similar in amplitude to the two-point shear signal at these survey depths, third-order statistics therefore offer a promising new way to constrain models of intrinsic galaxy alignments. Early shallow data from the next generation of very wide weak lensing surveys will be optimal for this type of study.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据