Testing Gravity with Weak Gravitational Lensing

Abstract:

The universe is currently going through a phase of accelerated expansion. Currently explained by a dark energy, this observation drives the question I am working on: could it instead be the hint that General Relativity, our theory of gravity, does not hold on cosmological scales? The goal of my research is to answer this question using the data from the Dark Energy Survey (DES), the current largest weak lensing experiment. In the first part of this talk, I will explain why weak gravitational lensing is a powerful tool to test gravity and show the effort from the team I coordinate in the DES collaboration to use weak lensing data to test General Relativity. In the second part of my talk I will describe and show the latest results of a new approach I proposed to efficiently test gravity with future surveys such as NASA Roman telescope. The aim of this study, which was awarded a grant from the JPL Data Science Working Group, is to classify the numerous alternative theories of gravity using Self-Organizing Map. This will help determine the theories of gravity to be tested with future surveys.  

About the speaker:

Dr. Agnès Ferté earned her PhD at the Institut d’Astrophysique Spatiale (Université Paris Sud), focusing on the polarized anisotropies of the Cosmic Microwave Background. She moved to Edinburgh (UK) for a 3-year postdoc at the Royal Observatory, Edinburgh where she joined the Dark Energy Survey (DES) collaboration and studied the recent cosmic acceleration.  She joined JPL in August 2018 to work on challenging the standard model of cosmology with DES and on solving the issues arising from high-precision weak gravitational lensing measurements.