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The Bernardeau-Nishimichi-Taruya (BNT) transform provides a powerful framework for analysing tomographic cosmic shear data by improving the localization of shear correlations in physical scale. It operates by performing a linear combination…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-23 Shiming Gu , Ludovic van Waerbeke , Francis Bernardeau , Sébastien Fabbro

We present an analysis comparing nulling strategies for reducing the impact of baryon feedback on cosmic shear measurements. We consider three different approaches which aim to `null' the high-$k$ modes using transformations applied to the…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-06 Naomi Clare Robertson , Alex Hall

If left unchecked modeling uncertainties at small scales, due to poorly understood baryonic physics and non-linear structure formation, will significantly bias Stage IV cosmic shear two-point statistic parameter constraints. While it is…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-17 Peter L. Taylor , Francis Bernardeau , Thomas D. Kitching

In tomographic cosmic-shear observations, the BNT (Bernardeau, Nishimichi, Taruya) transform, Bernardeau et al. (2014), allows to build weak lensing transformed maps for which the contribution from low redshift lenses is nulled. As this…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-23 David Touzeau , Francis Bernardeau , Karim Benabed , Sandrine Codis

The precision of Stage IV cosmic shear surveys will enable us to probe smaller physical scales than ever before, however, model uncertainties from baryonic physics and non-linear structure formation will become a significant concern. The…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-27 Anurag C. Deshpande , Peter L. Taylor , Thomas D. Kitching

Standard cosmological weak lensing analyses using cosmic shear are inevitably sensitive to small-scale, non-linear clustering from low-redshift structures. The need to adequately model the clustering of matter on this non-linear regime,…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-25 Giulia Piccirilli , Matteo Zennaro , Carlos García-García , David Alonso

In the context of tomographic cosmic shear surveys, there exists a nulling transformation of weak lensing observations (also called BNT transform) that allows us to simplify the correlation structure of tomographic cosmic shear…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-28 Alexandre Barthelemy , Francis Bernardeau , Sandrine Codis , Cora Uhlemann

We present a joint weak lensing and X-ray analysis of 4 deg$^2$ from the CFHTLS and XMM-LSS surveys. Our weak lensing analysis is the first analysis of a real survey using shapelets, a new generation weak lensing analysis method. We create…

Weak-gravitational lensing tends to wash out scale and time-dependent features of the clustering of matter, such as the Baryonic Acoustic Oscillations (BAO) which appear in the form of wiggles in the matter power spectrum but that disappear…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-02 David Touzeau , Alexandre Barthelemy , Francis Bernardeau

The next generation of weak lensing surveys will measure the matter distribution of the local Universe with unprecedented precision, allowing the resolution of non-Gaussian features of the convergence field. This encourages the use of…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-17 Dominik Zürcher , Janis Fluri , Virginia Ajani , Silvan Fischbacher , Alexandre Refregier , Tomasz Kacprzak

The scattering transform is a wavelet-based statistic capable of capturing non-Gaussian features in weak lensing (WL) convergence maps and has been proven to tighten cosmological parameter constraints by accessing information beyond…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-14 Mariia Marinichenko , Marcel P. van Daalen , Elena Sellentin , Jeger C. Broxterman , Matthieu Schaller , Joop Schaye

Bayesian Last Layers (BLLs) provide a convenient and computationally efficient way to estimate uncertainty in neural networks. However, they underestimate epistemic uncertainty because they apply a Bayesian treatment only to the final…

As weak lensing surveys become deeper, they reveal more non-Gaussian aspects of the convergence field which can only be extracted using statistics beyond the power spectrum. In Cheng et al. (2020) we showed that the scattering transform, a…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-07 Sihao Cheng , Brice Ménard

Non-Gaussian statistics of the projected weak lensing field are powerful estimators that can outperform the constraining power of the two-point functions in inferring cosmological parameters. This is because these estimators extract the…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-31 Daniela Grandón , Elena Sellentin

$ $Weak gravitational lensing is a powerful probe which is used to constrain the standard cosmological model and its extensions. With the enhanced statistical precision of current and upcoming surveys, high accuracy predictions for weak…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Ting Tan , Dominik Zuercher , Janis Fluri , Alexandre Refregier , Federica Tarsitano , Tomasz Kacprzak

We present a novel statistic to extract cosmological information in weak lensing data: the lensing minima. We also investigate the effect of baryons on the cosmological constraints from peak and minimum counts. Using the \texttt{MassiveNuS}…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-06 William R. Coulton , Jia Liu , Ian G. McCarthy , Ken Osato

We use numerical simulations of ray tracing through N-body simulations to investigate weak lensing by large-scale structure. These are needed for testing the analytic predictions of two-point correlators, to set error estimates on them and…

Astrophysics · Physics 2007-05-23 Bhuvnesh Jain , Uros Seljak , Simon White

Analyses of cosmic shear typically condense weak lensing information over a range of scales to a single cosmological parameter, $S_8$. This paper presents a method to extract more information from Stage-IV cosmic shear measurements by…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-30 Calvin Preston , Alexandra Amon , George Efstathiou

The capacity of Stage IV lensing surveys to measure the neutrino mass sum and differentiate between the normal and inverted mass hierarchies depends on the impact of nuisance parameters describing small-scale baryonic astrophysics and…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-09 David Copeland , Andy Taylor , Alex Hall

One of the most powerful techniques to study the dark sector of the Universe is weak gravitational lensing. In practice, to infer the reduced shear, weak lensing measures galaxy shapes, which are the consequence of both the intrinsic…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-07 Sami-Matias Niemi , Thomas Kitching , Mark Cropper
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