Princeton University Thunch Talk

Weak gravitational lensing of the large scale structure of the Universe has been identified as a powerful way to learn about dark matter and dark energy, two largely unknown components of the Universe that make up 95% of its matter-energy contents. As such, weak lensing is one of the fundamental tools used by past, current, and future projects such as the Dark Energy Survey (DES), the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), and NASA's Nancy Grace Roman Space Telescope (Roman). Nevertheless, the extraction of the weak gravitational lensing signal from astronomical measurements is a challenging process, and great attention must be placed on the understanding and characterization of systematic errors. In this talk, I will discuss the challenges of Point Spread Function (PSF) modeling and shape measurement for weak gravitational lensing science with DES, LSST, and Roman. In particular, I will discuss the characterization and mitigation of detector effects such as the "tree rings" and the "brighter-fatter effect" in the fully-depleted, thick CCDs of the Dark Energy Camera and the LSST Camera, and in the near-infrared H4RG detectors of Roman. I will frame these investigations in the context of the main results from DES Year 1 and results from DES Year 3 data.