A general framework for removing point-spread function additive systematics in cosmological weak lensing analysis

Tianqing Zhang; Xiangchong Li; Roohi Dalal; Rachel Mandelbaum; Michael A. Strauss; Arun Kannawadi; Hironao Miyatake; Andrina Nicola; Andres A.Plazas Malagón; Masato Shirasaki; Sunao Sugiyama; Masahiro Takada; Surhud More

doi:10.1093/mnras/stad1801

A general framework for removing point-spread function additive systematics in cosmological weak lensing analysis

Tianqing Zhang, Xiangchong Li, Roohi Dalal, Rachel Mandelbaum, Michael A. Strauss, Arun Kannawadi, Hironao Miyatake, Andrina Nicola, Andres A.Plazas Malagón, Masato Shirasaki, Sunao Sugiyama, Masahiro Takada, Surhud More

Princeton University

Research output: Contribution to journal › Article › peer-review

Abstract

Cosmological weak lensing measurements rely on a precise measurement of the shear two-point correlation function (2PCF) along with a deep understanding of systematics that affect it. In this work, we demonstrate a general framework for detecting and modelling the impact of PSF systematics on the cosmic shear 2PCF and mitigating its impact on cosmological analysis. Our framework can detect PSF leakage and modelling error from all spin-2 quantities contributed by the PSF second and higher moments, rather than just the second moments, using the cross-correlations between galaxy shapes and PSF moments. We interpret null tests using the HSC Year 3 (Y3) catalogs with this formalism and find that leakage from the spin-2 combination of PSF fourth moments is the leading contributor to additive shear systematics, with total contamination that is an order-of-magnitude higher than that contributed by PSF second moments alone. We conducted a mock cosmic shear analysis for HSC Y3 and find that, if uncorrected, PSF systematics can bias the cosmological parameters m and S8 by ∼0.3σ. The traditional second moment-based model can only correct for a 0.1σ bias, leaving the contamination largely uncorrected. We conclude it is necessary to model both PSF second and fourth moment contaminations for HSC Y3 cosmic shear analysis. We also reanalyse the HSC Y1 cosmic shear analysis with our updated systematics model and identify a 0.07σ bias on m when using the more restricted second moment model from the original analysis. We demonstrate how to self-consistently use the method in both real space and Fourier space, assess shear systematics in tomographic bins, and test for PSF model overfitting.

Original language	American English
Pages (from-to)	2441-2471
Number of pages	31
Journal	Monthly Notices of the Royal Astronomical Society
Volume	525
Issue number	2
DOIs	https://doi.org/10.1093/mnras/stad1801
State	Published - Oct 1 2023

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Keywords

gravitational lensing: weak
methods: data analysis

Access to Document

10.1093/mnras/stad1801

Cite this

Zhang, T., Li, X., Dalal, R., Mandelbaum, R., Strauss, M. A., Kannawadi, A., Miyatake, H., Nicola, A., Malagón, A. A. P., Shirasaki, M., Sugiyama, S., Takada, M., & More, S. (2023). A general framework for removing point-spread function additive systematics in cosmological weak lensing analysis. Monthly Notices of the Royal Astronomical Society, 525(2), 2441-2471. https://doi.org/10.1093/mnras/stad1801

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title = "A general framework for removing point-spread function additive systematics in cosmological weak lensing analysis",

abstract = "Cosmological weak lensing measurements rely on a precise measurement of the shear two-point correlation function (2PCF) along with a deep understanding of systematics that affect it. In this work, we demonstrate a general framework for detecting and modelling the impact of PSF systematics on the cosmic shear 2PCF and mitigating its impact on cosmological analysis. Our framework can detect PSF leakage and modelling error from all spin-2 quantities contributed by the PSF second and higher moments, rather than just the second moments, using the cross-correlations between galaxy shapes and PSF moments. We interpret null tests using the HSC Year 3 (Y3) catalogs with this formalism and find that leakage from the spin-2 combination of PSF fourth moments is the leading contributor to additive shear systematics, with total contamination that is an order-of-magnitude higher than that contributed by PSF second moments alone. We conducted a mock cosmic shear analysis for HSC Y3 and find that, if uncorrected, PSF systematics can bias the cosmological parameters m and S8 by ∼0.3σ. The traditional second moment-based model can only correct for a 0.1σ bias, leaving the contamination largely uncorrected. We conclude it is necessary to model both PSF second and fourth moment contaminations for HSC Y3 cosmic shear analysis. We also reanalyse the HSC Y1 cosmic shear analysis with our updated systematics model and identify a 0.07σ bias on m when using the more restricted second moment model from the original analysis. We demonstrate how to self-consistently use the method in both real space and Fourier space, assess shear systematics in tomographic bins, and test for PSF model overfitting.",

keywords = "gravitational lensing: weak, methods: data analysis",

author = "Tianqing Zhang and Xiangchong Li and Roohi Dalal and Rachel Mandelbaum and Strauss, {Michael A.} and Arun Kannawadi and Hironao Miyatake and Andrina Nicola and Malag{\'o}n, {Andres A.Plazas} and Masato Shirasaki and Sunao Sugiyama and Masahiro Takada and Surhud More",

note = "Publisher Copyright: {\textcopyright} 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.",

year = "2023",

month = oct,

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doi = "10.1093/mnras/stad1801",

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Zhang, T, Li, X, Dalal, R, Mandelbaum, R, Strauss, MA, Kannawadi, A, Miyatake, H, Nicola, A, Malagón, AAP, Shirasaki, M, Sugiyama, S, Takada, M & More, S 2023, 'A general framework for removing point-spread function additive systematics in cosmological weak lensing analysis', Monthly Notices of the Royal Astronomical Society, vol. 525, no. 2, pp. 2441-2471. https://doi.org/10.1093/mnras/stad1801

TY - JOUR

T1 - A general framework for removing point-spread function additive systematics in cosmological weak lensing analysis

AU - Zhang, Tianqing

AU - Li, Xiangchong

AU - Dalal, Roohi

AU - Mandelbaum, Rachel

AU - Strauss, Michael A.

AU - Kannawadi, Arun

AU - Miyatake, Hironao

AU - Nicola, Andrina

AU - Malagón, Andres A.Plazas

AU - Shirasaki, Masato

AU - Sugiyama, Sunao

AU - Takada, Masahiro

AU - More, Surhud

PY - 2023/10/1

Y1 - 2023/10/1

N2 - Cosmological weak lensing measurements rely on a precise measurement of the shear two-point correlation function (2PCF) along with a deep understanding of systematics that affect it. In this work, we demonstrate a general framework for detecting and modelling the impact of PSF systematics on the cosmic shear 2PCF and mitigating its impact on cosmological analysis. Our framework can detect PSF leakage and modelling error from all spin-2 quantities contributed by the PSF second and higher moments, rather than just the second moments, using the cross-correlations between galaxy shapes and PSF moments. We interpret null tests using the HSC Year 3 (Y3) catalogs with this formalism and find that leakage from the spin-2 combination of PSF fourth moments is the leading contributor to additive shear systematics, with total contamination that is an order-of-magnitude higher than that contributed by PSF second moments alone. We conducted a mock cosmic shear analysis for HSC Y3 and find that, if uncorrected, PSF systematics can bias the cosmological parameters m and S8 by ∼0.3σ. The traditional second moment-based model can only correct for a 0.1σ bias, leaving the contamination largely uncorrected. We conclude it is necessary to model both PSF second and fourth moment contaminations for HSC Y3 cosmic shear analysis. We also reanalyse the HSC Y1 cosmic shear analysis with our updated systematics model and identify a 0.07σ bias on m when using the more restricted second moment model from the original analysis. We demonstrate how to self-consistently use the method in both real space and Fourier space, assess shear systematics in tomographic bins, and test for PSF model overfitting.

AB - Cosmological weak lensing measurements rely on a precise measurement of the shear two-point correlation function (2PCF) along with a deep understanding of systematics that affect it. In this work, we demonstrate a general framework for detecting and modelling the impact of PSF systematics on the cosmic shear 2PCF and mitigating its impact on cosmological analysis. Our framework can detect PSF leakage and modelling error from all spin-2 quantities contributed by the PSF second and higher moments, rather than just the second moments, using the cross-correlations between galaxy shapes and PSF moments. We interpret null tests using the HSC Year 3 (Y3) catalogs with this formalism and find that leakage from the spin-2 combination of PSF fourth moments is the leading contributor to additive shear systematics, with total contamination that is an order-of-magnitude higher than that contributed by PSF second moments alone. We conducted a mock cosmic shear analysis for HSC Y3 and find that, if uncorrected, PSF systematics can bias the cosmological parameters m and S8 by ∼0.3σ. The traditional second moment-based model can only correct for a 0.1σ bias, leaving the contamination largely uncorrected. We conclude it is necessary to model both PSF second and fourth moment contaminations for HSC Y3 cosmic shear analysis. We also reanalyse the HSC Y1 cosmic shear analysis with our updated systematics model and identify a 0.07σ bias on m when using the more restricted second moment model from the original analysis. We demonstrate how to self-consistently use the method in both real space and Fourier space, assess shear systematics in tomographic bins, and test for PSF model overfitting.

KW - gravitational lensing: weak

KW - methods: data analysis

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U2 - 10.1093/mnras/stad1801

DO - 10.1093/mnras/stad1801

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VL - 525

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JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 2

ER -

A general framework for removing point-spread function additive systematics in cosmological weak lensing analysis

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Keywords

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