Speaker
Description
Weak gravitational lensing is a well-studied and valuable cosmological probe. Due to the complex path taken by a multipally-lensed photon, weak lensing analysis generally integrates the gravitational potential along the line of sight. This is known as the Born approximation. Accurately accounting for the effects from multiple weak lensing events requires the use of post-Born corrections. Post-Born lensing of the cosmic microwave background induces a significant bispectrum, which will be important for upcoming surveys with increasing precision. In this talk I outline the second-order post-Born correction terms, namely lens-lens coupling and ray deflection. We present a template for reconstructing the post-Born lensing convergence of the cosmic microwave background via a quadratic estimator. Finally, we test the validity of the template using Gaussian simulations and the AGORA $N$-body simulation suite.