3:30–4:30 pm ERC 401
Host: Alex Drlica-Wagner
Masaya Yamamoto (Duke University) "Cosmic Shear with Roman: Challenges and Lookouts on How to Deliver Cosmology with Space-Based Data"
With next-generation imaging surveys such as the Vera C. Rubin Observatory Legacy Survey of Space and Time (Rubin LSST) and the Nancy G. Roman Space Telescope (Roman), there is immense new promise in understanding the fundamental nature of dark matter and dark energy. To achieve these scientific outcomes, the challenges of determining galaxy shapes and redshifts and modeling the impact of astrophysical effects must be solved. While the data quality of space-based imaging is generally much better than ground-based imaging, science requirements are much more stringent and these space-based observations pose new challenges that need to be addressed differently from ground-based observations. One of the main challenges for WL in Roman is that individual images will be undersampled. In this talk, I will present challenges associated with measuring shear with undersampled imaging and methods to mitigate the impact of aliasing on weak lensing cosmology.
Daniel Gilman (UChicago) "A guided tour of dark matter physics with quadruply-imaged quasars"
Theories of dark matter make different predictions for the abundance and internal structure of dark matter halos. Thus, inferences of the properties of halos can be recast as constraints on dark matter physics, or any other physical process that alters the primordial density field and the subsequent evolution of dark matter structure throughout cosmic time. Strong gravitational lensing provides a unique and powerful way to characterize the properties of dark halos because lensing depends only on gravity. I will discuss how we can use strong lensing to constrain the nature of dark matter, highlighting applications to a variety of dark matter models (warm, fuzzy, and self-interacting dark matter). I will also discuss a Cycle 1 JWST program that will observe 31 lensed quasars in the mid-IR, allowing us to push detection of dark matter structure below 10^7 solar masses, well below the threshold of galaxy formation.
