Institute for Advanced Study/Princeton University Early Universe/Cosmology Lunch Discussion

Intrinsic-Alignments are one of the main systematic effects hindering the robust interpretation of weak-lensing measurements. In this talk I will describe several works by which my collaborators and I advance the modelling and understanding of IA in the mildly non-linear regime. I will describe HYMALAIA, a model based on a combination of a Lagrangian bias expansion with the non-linear displacements of matter from N-Body simulations, and show how it can correctly describe IA power spectra well into the non-linear regime. I will also describe a newly developed method to measure shape-bias parameters fast and precisely, and our application of it to measure galaxy shape-bias parameters from the MillenniumTNG simulation. Finally, I will describe an innovative simulation suite which will allow us to probe for the first time the relation between IA and baryonic feedback effects.