On July 5, 2023 five Project Infrastructure Teams were selected by NASA to build the infrastructure for its upcoming flaghip mission, the Nancy Grace Roman Space Telescope. Our team was selected to develop, implement, and validate a weak lensing (WL) measurement and analysis infrastructure that can process the first year of Nancy Grace Roman Space Telescope's High-Latitude Imaging Survey (HLIS) data towards a better unferstanding of cosmology, gravity, and fundamental physics. Our initial team consists of 39 members from 17 US institutions as well as France and Japan. Around the US, our team members are based at Carnegie Mellon University, Cornell University, Duke University, Goddard Space Flight Center / NASA, Jet Propulsion Laboratory, IPAC / Caltech, New York University, Northeastern University, Ohio State University, Princeton University, Stony Brook University, UC Santa Cruz, University of Arizona, University of Chicago, University of Pennsylvania, University of Pittsburgh, and University of Washington. We expect the team will grow significantly over the coming years.

The most surprising cosmological discovery of the last decades has been the demonstration that the expansion of the universe is accelerating rather than decelerating. We have since measured the cosmic expansion history by multiple methods with much greater precision over a wide range of redshift, but understanding the origin of cosmic acceleration remains one of the most pressing unsolved problems in fundamental physics. Alongside the expansion history, one can probe the physics of cosmic acceleration by measuring the growth of matter clustering from primordial fluctuations measured in the cosmic microwave background (CMB) to low redshift structure measured through weak gravitational lensing or redshift-space distortions of the galaxy distribution. Measurements of structure growth are especially important for distinguishing theories that explain cosmic acceleration with an exotic energy component (a cosmological constant or more general “dark energy”) from theories that modify general relativity itself. Roman will be one of the most powerful facilities for weak lensing cosmology ever built; compared to the Vera C. Rubin Observatory’s Legacy Survey of Space and Time (hereafter LSST), Roman is expected to measure a similar number of galaxy shapes per unit observing time with the high angular resolution and stability afforded by space-based observations. Forecasts imply that cosmological weak lensing in a 2000 square degree high-latitude imaging survey (HLIS) with Roman could lead to an order of magnitude improvement in precision over current measurements. Cross-correlations with galaxies and the masses and abundance of galaxy clusters will provide valuable additional cosmological information. To realize Roman’s cosmological goals, it is critical to control sources of systematic uncertainty and extract information from small scales and non-Gaussian statistics that are enabled by the gains in redshift coverage, galaxy number density and the quality of space based imaging with Roman. These measurements have the potential to revolutionize our understanding of cosmology, gravity, and fundamental physics.

This team is executing a program of infrastructure development that will enable the Roman high-latitude imaging survey to achieve its extraordinary cosmological potential, while simultaneously providing unprecedented volumes of exquisite data for an enormous range of astrophysical investigations.

Besides our scientific committment, our proposal was selected also for our Diversity, Equity, and Inclusion Program, where we have committed to building an inclusive management and organizational structure from the ground up, for our initiatives towards diversity, equity and inclusion, and defining inclusion as a core value for the team. More about our inclusion program to come soon to our Governance page.