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Extracting cosmological information from weak lensing bispectrum

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I plan to introduce a statistic called the Integrated Bispectrum (IB)to probe gravity-induced non-Gaussianity at the level of bispectrum from weak lensing maps. I will discuss how to generalize the concept of the IB to spherical coordinates, and to three-dimensions (3D) using a spherical-Bessel decomposition. These results will next be connected to the response function approach. I will also introduce the related concept of squeezed three-point correlation functions (3PCF) for convergence maps and relate them to the IB defined in the Fourier domain. Next, I will demonstrate how IB can be computed using a variety of analytical approachesincluding the ones based on Tree-Level Standard Perturbation Theory (SPT), Effective Field Theory (EFT), Halo models and models based on the Separate Universe approach. Generalization to include tomographic bins, external data sets, and Bayesian estimators will be discussed. I will show results from the Euclid Flagship simulations to test analytical results as a function of redshift and wave number. Generalization to shear maps and construction of squeezed limits of EEE , BBB, EEB and EBB bispectra will also be discussed. Finally, I plan to show how external data sets, e.g. y-parameter maps from thermal Sunyaev-Zel’dovich (tSZ)observations can be used to construct the squeezed limits of mixed IB involving y and convergence fields.

This talk is part of the Cosmology Lunch series.

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