PSF anisotropy and systematic errors in weak lensing surveys
نویسندگان
چکیده
منابع مشابه
PSF Anisotropy and Systematic Errors in Weak Lensing Surveys
Given the basic parameters of a cosmic shear weak lensing survey, how well can systematic errors due to anisotropy in the point spread function (PSF) be corrected? The largest source of error in this correction to date has been the interpolation of the PSF to the locations of the galaxies. To address this error, we separate the PSF patterns into components that recur in multiple exposures/point...
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We introduce a new algorithm for interpolating measurements of the point-spread function (PSF) using stars from many exposures. The principal components of the variation in the PSF pattern from multiple exposures are used to solve for better fits for each individual exposure. These improved fits are then used to correct the weak lensing shapes. Since we expect some degree of correlation in the ...
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We have developed a new technique for weak lensing analysis, with which the effect of the point spread function (PSF) on small galaxy images can be corrected for accurately. Rather than relying on weighted second moments of detected images, which we show can leave residuals at the level of a percent in the shear, we directly fit (stacked or individual) galaxy images as PSFconvolved, sheared cir...
متن کاملSystematic errors in future weak-lensing surveys: requirements and prospects for self-calibration
We study the impact of systematic errors on planned weak-lensing surveys and compute the requirements on their contributions so that they are not a dominant source of the cosmological parameter error budget. The generic types of error we consider are multiplicative and additive errors in measurements of shear, as well as photometric redshift errors. In general, more powerful surveys have strong...
متن کاملThe Impact of Non-Gaussian Errors on Weak Lensing Surveys
The weak lensing power spectrum carries cosmological information via its dependence on the growth of structure and on geometric factors. Since much of the cosmological information comes from scales affected by nonlinear clustering, measurements of the lensing power spectrum can be degraded by non-Gaussian covariances. Recently there have been conflicting studies about the level of this degradat...
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ژورنال
عنوان ژورنال: Journal of Cosmology and Astroparticle Physics
سال: 2006
ISSN: 1475-7516
DOI: 10.1088/1475-7516/2006/02/001