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KiDS-1000: cosmic shear with enhanced redshift calibration

Van Den Busch, J L; Wright, A H; Hildebrandt, H; Bilicki, M; Asgari, M; Joudaki, S; Blake, C; Heymans, C; Kannawadi, A; Shan, H Y; Tröster, T

Authors

J L Van Den Busch

A H Wright

H Hildebrandt

M Bilicki

M Asgari

S Joudaki

C Blake

C Heymans

A Kannawadi

H Y Shan

T Tröster



Abstract

We present a cosmic shear analysis with an improved redshift calibration for the fourth data release of the Kilo-Degree Survey (KiDS-1000) using self-organising maps (SOMs). Compared to the previous analysis of the KiDS-1000 data, we expand the redshift calibration sample to more than twice its size, now consisting of data of 17 spectroscopic redshift campaigns, and significantly extending the fraction of KiDS galaxies we are able to calibrate with our SOM redshift methodology. We then enhance the calibration sample with precision photometric redshifts from COSMOS2015 and the Physics of the Accelerated Universe Survey (PAUS), allowing us to fill gaps in the spectroscopic coverage of the KiDS data. Finally we perform a Complete Orthogonal Sets of E/B-Integrals (COSEBIs) cosmic shear analysis of the newly calibrated KiDS sample. We find S 8 = 0.748 +0.021 −0.025 , which is in good agreement with previous KiDS studies and increases the tension with measurements of the cosmic microwave background to 3.4σ. We repeat the redshift calibration with different subsets of the full calibration sample and obtain, in all cases, agreement within at most 0.5σ in S 8 compared to our fiducial analysis. Including additional photometric redshifts allows us to calibrate an additional 6 % of the source galaxy sample. Even though further systematic testing with simulated data is necessary to quantify the impact of redshift outliers, precision photometric redshifts can be beneficial at high redshifts and to mitigate selection effects commonly found in spectroscopically selected calibration samples.

Citation

Van Den Busch, J. L., Wright, A. H., Hildebrandt, H., Bilicki, M., Asgari, M., Joudaki, S., …Tröster, T. (in press). KiDS-1000: cosmic shear with enhanced redshift calibration. Astronomy and Astrophysics, https://doi.org/10.1051/0004-6361/202142083

Journal Article Type Article
Acceptance Date Apr 4, 2022
Online Publication Date Jun 8, 2022
Deposit Date Apr 6, 2022
Publicly Available Date Mar 29, 2024
Journal Astronomy and Astrophysics
Print ISSN 0004-6361
Publisher EDP Sciences
Peer Reviewed Peer Reviewed
DOI https://doi.org/10.1051/0004-6361/202142083
Keywords Cosmology: observations; Gravitational lensing: weak; Galaxies: distances and redshifts; Surveys
Public URL https://hull-repository.worktribe.com/output/3965289

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