TY - JOUR
T1 - KiDS-Legacy calibration
T2 - Unifying shear and redshift calibration with the SKiLLS multi-band image simulations
AU - Li, Shun Sheng
AU - Kuijken, Konrad
AU - Hoekstra, Henk
AU - Miller, Lance
AU - Heymans, Catherine
AU - Hildebrandt, Hendrik
AU - Van Den Busch, Jan Luca
AU - Wright, Angus H.
AU - Yoon, Mijin
AU - Bilicki, MacIej
AU - Bravo, Matías
AU - Lagos, Claudia Del P.
N1 - Funding Information:
We thank Fedor Getman for providing the deep VST-COSMOS catalogue and Arun Kannawadi for reading the manuscript and providing useful comments. We also wish to thank other members of the KiDS-Legacy Calibration Working Group (especially Benjamin Joachimi, Benjamin Stölzner and Anna Wittje) for informative discussions and suggestions through numerous teleconferences. This work used the compute resources from the Academic Leiden Interdisciplinary Cluster Environment (ALICE) provided by Leiden University. We acknowledge support from: the Netherlands Research School for Astronomy (SSL); the Royal Society and Imperial College (KK); the Netherlands Organisation for Scientific Research (NWO) under Vici grant 639.043.512 (HHo); and the UK Science and Technology Facilities Council (STFC) under grant ST/N000919/1 (LM) and ST/V000594/1 (CH). We also acknowledge support from the European Research Council (ERC) under grant agreement No. 647112 (CH) and No. 770935 (HHi, JLvdB, AHW); the Max Planck Society and the Alexander von Humboldt Foundation in the framework of the Max Planck-Humboldt Research Award endowed by the Federal Ministry of Education and Research (CH, MY); the Deutsche Forschungsgemeinschaft Heisenberg grant Hi 1495/5-1 (HHi); the Polish National Science Center through grants no. 2020/38/E/ST9/00395, 2018/30/E/ST9/00698, 2018/31/G/ST9/03388 and 2020/39/B/ST9/03494 (MBi); the Polish Ministry of Science and Higher Education through grant DIR/WK/2018/12 (MBi); the University of Western Australia through a Scholarship for International Research Fees and Ad Hoc Postgraduate Scholarship (MBr); and the ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) through project number CE170100013 (CL). The results in this paper are based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme IDs: 088.D-4013, 092.A-0176, 092.D-0370, 094.D-0417, 177.A-3016, 177.A-3017, 177.A-3018 and 179.A-2004, and on data products produced by the KiDS consortium. The KiDS production team acknowledges support from: Deutsche Forschungsgemeinschaft, ERC, NOVA and NWO-M grants; Target; the University of Padova, and the University Federico II (Naples). Contributions to the data processing for VIKING were made by the VISTA Data Flow System at CASU, Cambridge and WFAU, Edinburgh. The SURFS-S HARK simulations were produced at the Pawsey Supercomputing Centre with funding from the Australian Government and the Government of Western Australia. Author contributions: All authors contributed to the development and writing of this paper. The authorship list is given in three groups: the lead authors (SSL, KK, HHo, LM) followed by two alphabetical groups. The first alphabetical group includes those who are key contributors to both the scientific analysis and the data products. The second group covers those who have either made a significant contribution to the data products, or to the scientific analysis.
Publisher Copyright:
© 2023 The Authors.
PY - 2023/2/1
Y1 - 2023/2/1
N2 - We present SKiLLS, a suite of multi-band image simulations for the weak lensing analysis of the complete Kilo-Degree Survey (KiDS), dubbed KiDS-Legacy analysis. 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 integrated cosmological simulations with high-quality imaging observations. We also improved 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 accounted for the impact of blended systems at different redshifts. Although the overall correction is minor, we found 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 explored the impact of the PSF modelling errors and found a small yet noticeable effect on the shear bias. Finally, we conducted 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.
AB - We present SKiLLS, a suite of multi-band image simulations for the weak lensing analysis of the complete Kilo-Degree Survey (KiDS), dubbed KiDS-Legacy analysis. 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 integrated cosmological simulations with high-quality imaging observations. We also improved 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 accounted for the impact of blended systems at different redshifts. Although the overall correction is minor, we found 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 explored the impact of the PSF modelling errors and found a small yet noticeable effect on the shear bias. Finally, we conducted 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.
KW - Gravitational lensing: weak
KW - Methods: data analysis
KW - Methods: statistical
KW - Techniques: image processing
UR - http://www.scopus.com/inward/record.url?scp=85148521134&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/202245210
DO - 10.1051/0004-6361/202245210
M3 - Article
AN - SCOPUS:85148521134
SN - 0004-6361
VL - 670
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
M1 - A100
ER -