My main area of research is weak gravitational lensing, the very small perturbations in the shapes of distant source galaxies due to massive foreground galaxies/clusters. There are many useful applications of weak lensing due to the fact that it is sensitive to the full matter density projected along the line of sight, regardless of whether that matter is luminous (i.e., visible through a telescope) or not (dark matter). I am interested in applications of lensing to the study of the connection between galaxy observables and their underlying dark matter halos, of how cosmic structure grows with time (connected to dark energy), and of whether General Relativity is really the correct theory of gravity on cosmological scales. Much of this work involves combining gravitational lensing with other types of cosmological measurements. Recently I have been working on applications of methods from statistics and machine learning to cosmological problems involving large datasets, and am a participant in CMU's NSF AI Planning Institute for Data-Driven Discovery in Physics.
One exciting aspect of my research activity is the data release from the Hyper Suprime-Cam Subaru Strategic Program. The first public data release (PDR1) includes about 100 square degrees of data in 5 bands to full depth, while the second and third data releases greatly increase that area. Check them out! The PDR1 weak lensing catalogs were made available in a later release, and should enable weak lensing cosmological analysis to be carried out by anybody. The HSC Year 3 cosmology results have been published, and data products will be made public in early 2024.
From July 2019 - June 2021, I spent a lot of my time as the Spokesperson of the LSST Dark Energy Science Collaboration (DESC), preparing for high-accuracy and high-precision cosmology with the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). The "Introduction to DESC" slides are a great place to get started learning, and you can find links to collaboration publications, datasets, software, policies, and other information on the DESC website. I remain an active member of the collaboration, and am the lead at CMU for the LINCC Frameworks Initiative, which is providing analysis software infrastructure for several LSST science cases.
In 2023, I spent a lot of time serving on the Particle Physics Project Prioritization Panel (P5), for which the report was accepted in December 2023.
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