Shear Madness: Taming Systematics in Stage IV Surveys (Nikolina Šarčević, Duke University)

par Nikolina Šarčević

lundi 3 nov. 2025, 14:00 → 16:00 Europe/Paris

amphi Charpak

In the era of Stage IV cosmological surveys such as LSST and Roman, achieving precise cosmological constraints through weak gravitational lensing requires careful treatment of astrophysical systematics and redshift distribution uncertainties. In this talk, I will introduce the fundamentals of weak lensing cosmology and provide an overview of how key astrophysical systematics—including galaxy bias, baryonic feedback, and intrinsic alignments—as well as uncertainties in photometric redshift distributions, impact cosmological parameter estimation. I will highlight the challenges they pose, the scales they affect, and the importance of accurate modeling for Stage IV analyses. Drawing from recent research, including my own work on baryonic feedback, I will present examples of how these systematics suppress power on small scales and degrade parameter constraints, showcasing both individual results and broader community efforts. Finally, I will touch on computational and open-source tools being developed to support robust cosmological analyses in the face of these challenges.