Neta Assaf Bahcall

Laid the foundation for the use of clusters of galaxies -- the most massive gravitationally bound systems in the universe -- as fundamental probes of Cosmology, and as powerful tracers of the distribution of large-scale structure in the universe. Used clusters to trace the existence of the largest scale structures, and showed that measurements of cluster abundance as a function of mass and redshift can determine both the mass-density of the universe and the initial amplitude of mass fluctuations. Showed that the existence of significant number of clusters at high redshift implies that we live in a low-density universe. Determined the relationship between mass and light as a function of scale and showed it indicates that we live in a low density universe. Her work has inspired many current large projects to identify clusters of galaxies in the early universe and to define their properties including the distribution of dark matter within them. Currently serves on the planning committee for the James Webb Space Telescope. Member, National Academy of Sciences; chair of the Astronomy section at the NAS (2016-2019).