http://arxiv.org/abs/2210.07163
We present SKiLLS, a suite of multi-band image simulations for the KiDS-Legacy analysis, the weak lensing analysis of the complete Kilo-Degree Survey. The resulting catalogues enable joint shear and redshift calibration, enhancing the realism and hence accuracy over previous efforts. To create a large volume of simulated galaxies with faithful properties and to a sufficient depth, we integrate cosmological simulations with high-quality imaging observations. We also improve the realism of simulated images by allowing the point spread function (PSF) to differ between CCD images, including stellar density variations and varying noise levels between pointings. Using realistic variable shear fields, we account for the impact of blended systems at different redshifts. Although the overall correction is minor, we find a clear redshift-bias correlation in the blending-only variable shear simulations, indicating the non-trivial impact of this higher-order blending effect. We also explore the impact of the PSF modelling errors and find a small but noticeable effect on the shear bias. Finally, we conduct a series of sensitivity tests, including changing the input galaxy properties. We conclude that our fiducial shape measurement algorithm, lensfit, is robust within the requirements of lensing analyses with KiDS. As for future weak lensing surveys with tighter requirements, we suggest further investments in understanding the impact of blends at different redshifts, improving the PSF modelling algorithm and developing the shape measurement method to be less sensitive to the galaxy properties.
S. Li, K. Kuijken, H. Hoekstra, et. al.
Fri, 14 Oct 22
62/75
Comments: 28 pages, 31 figures, 2 tables, submitted to A&A
You must be logged in to post a comment.