Justin Myles (Princeton University)
Date: Tue. October 28th, 2025, 11:30 am-12:30 pmAdd to Google Calendar
Studying Cosmology with Weak Gravitational Lensing in the Rubin LSST Decade
We are now in the era of measuring galaxy weak lensing with the Vera Rubin Observatory’s LSST, the Euclid Space Telescope, the Roman Space Telescope, and more. These large galaxy surveys promise to deliver extraordinary datasets to answer open questions about the nature of dark matter and dark energy, but they face science-limiting challenges arising from uncertainty inherent to imaging data. I will discuss the challenges facing the use of imaging galaxy surveys for astrophysics and cosmology and how to optimally use spectroscopic and near-infrared data to mitigate these problems for the next decade. The main ideas of this talk are the interconnected challenges of two primary cosmological probes of galaxy surveys: measuring galaxy weak lensing and characterizing galaxy clusters. I will share case studies in photometric redshift estimation and galaxy cluster mass calibration as entry points to understanding these interconnected problems. In addition to issues already critical to current analyses, I will outline problems expected to become more acute in LSST Year 1 and ongoing work toward solutions thereof. This talk will both explore the breadth of known obstacles to answering astrophysical and cosmological questions with galaxy surveys and discuss how combining optical spectroscopy, near-infrared imaging, and optical imaging is key to overcoming these obstacles.