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Estimating the Integrated Bispectrum from Weak Lensing Maps

Munshi, D; McEwen, JD; Kitching, T; Fosalba, P; Teyssier, R; Stadel, J; (2020) Estimating the Integrated Bispectrum from Weak Lensing Maps. Journal of Cosmology and Astroparticle Physics , 2020 , Article 043. 10.1088/1475-7516/2020/05/043. Green open access

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Abstract

We use a recently introduced statistic called Integrated Bispectrum (IB) to probe the gravity-induced non-Gaussianity at the level of the bispectrum from weak lensing convergence or $\kappa$ maps. We generalize the concept of the IB to spherical coordinates, This result is next connected to the response function approach. We introduce the concept of squeezed three-point correlation functions (3PCF) for $\kappa$ maps and relate them to the IB defined in the Fourier domain. Finally, we use the Euclid Flagship simulations to compute the IB as a function of redshift and wave number. We outline how IB can be computed using a variety of analytical approaches including ones based on Effective Field Theory (EFT), halo models and models based on the Separate Universe approach. Generalizations to include tomographic bins, external data sets and Bayesian estimators are discussed. Generalizations to shear maps and construction of squeezed limits of EEE, BBB, EEB and EEB bispectra are also discussed. We also show how external data sets, e.g. $y$-parameter maps from thermal Sunyaev-Zeldovich observations, can be used to construct the squeezed limits of mixed IB involving $y$ and $\kappa$ fields. We emphasize the role of the finite volume effect in numerical estimation of IB.

Type: Article
Title: Estimating the Integrated Bispectrum from Weak Lensing Maps
Open access status: An open access version is available from UCL Discovery
DOI: 10.1088/1475-7516/2020/05/043
Publisher version: https://doi.org/10.1088/1475-7516/2020/05/043
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Cosmology, Large-Scale Structure, Weak Lensing
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/10068179
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