Cosmic Shear Nulling as a geometrical cosmological probe: methodology and sensitivity to cosmological parameters and systematics

Fuente: arXiv
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Auteurs principaux: Touzeau, David, Bernardeau, Francis, Benabed, Karim, Codis, Sandrine
Format: Preprint
Publié: 2025
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author Touzeau, David
Bernardeau, Francis
Benabed, Karim
Codis, Sandrine
author_facet Touzeau, David
Bernardeau, Francis
Benabed, Karim
Codis, Sandrine
contents In tomographic weak lensing surveys, the presence of nulling properties reveals symmetries inherent in the data, which rely solely on the geometrical properties of the Universe. Ensuring its validity thus provides us with constraints on the cosmological parameters that describe the background evolution, particularly the redshift dependence of the cosmological angular distance. This forms the basis of the tomographic cosmic shear nulling test that we introduce here. We outline how such a test can be executed, what it can constrain, and its specific efficiency in constraining cosmological parameters. Additionally, we explore its sensitivity to astrophysical effects such as magnification bias and reduced shear corrections, as well as observational systematics like errors in the mean redshift of the source bins. Our findings indicate that in a scenario akin to that of Euclid, this nulling test can bring significant and complementary constraints on basic cosmological parameters such as $\{Ω_m,{\rm w}_0\}$, provided that the mean redshift of the bins are known at a level of $10^{-3}$. We conclude that the combination of nulling as a cosmological probe or a consistence test with usual weak lensing and galaxy clustering probes could allow to better keep systematics under control and bring more precise results in the future.
format Preprint
id arxiv_https___arxiv_org_abs_2502_02246
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cosmic Shear Nulling as a geometrical cosmological probe: methodology and sensitivity to cosmological parameters and systematics
Touzeau, David
Bernardeau, Francis
Benabed, Karim
Codis, Sandrine
Cosmology and Nongalactic Astrophysics
In tomographic weak lensing surveys, the presence of nulling properties reveals symmetries inherent in the data, which rely solely on the geometrical properties of the Universe. Ensuring its validity thus provides us with constraints on the cosmological parameters that describe the background evolution, particularly the redshift dependence of the cosmological angular distance. This forms the basis of the tomographic cosmic shear nulling test that we introduce here. We outline how such a test can be executed, what it can constrain, and its specific efficiency in constraining cosmological parameters. Additionally, we explore its sensitivity to astrophysical effects such as magnification bias and reduced shear corrections, as well as observational systematics like errors in the mean redshift of the source bins. Our findings indicate that in a scenario akin to that of Euclid, this nulling test can bring significant and complementary constraints on basic cosmological parameters such as $\{Ω_m,{\rm w}_0\}$, provided that the mean redshift of the bins are known at a level of $10^{-3}$. We conclude that the combination of nulling as a cosmological probe or a consistence test with usual weak lensing and galaxy clustering probes could allow to better keep systematics under control and bring more precise results in the future.
title Cosmic Shear Nulling as a geometrical cosmological probe: methodology and sensitivity to cosmological parameters and systematics
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2502.02246