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Weak lensing observables in relativistic N-body simulations

Francesca Lepori
University of Geneva, Switzerland

The standard weak-lensing map modeling is based on Newtonian N-body simulations, which adopt a perturbative formalism to describe the lensing map.
In this seminar I will present a fully geometrical method to extract weak-lensing observables from simulations, which includes all relevant effects from general relativity. This method is based on the relativistic N-body code gevolution and a post-processing ray-racer, that integrate the photon geodesics backwards from the observer to the emitters and solves the Sachs optical equations to compute lensing convergence, ellipticity and rotation of the image.
I will finally discuss the results that we obtained applying this method in a high-resolution relativistic N-body simulation: I will show the angular power spectra and one-point probability distribution functions for the weak-lensing variables, which are broadly in agreement with comparable Newtonian simulations. Our geometric approach, however, is more robust and flexible, and can therefore be applied consistently to non-standard cosmologies and modified theories of gravity.

2020 May 27, 16:00

Online broadcast (Zoom)

Instituto de Astrofísica e Ciências do Espaço Universidade do Porto Faculdade de Ciências da Universidade de Lisboa
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia