Judith Cohen

Judith G. Cohen is the Kate Van Nuys Page Professor of Astronomy, Emeritus, at the California Institute of Technology (Caltech) in the Division of Physics, Mathematics and Astronomy. Born in New York City and raised in Brooklyn, she earned a B.A. in astronomy from Radcliffe College in 1967 with a National Merit Scholarship, an M.S. from Caltech in 1969, and a Ph.D. from Caltech in 1971 under advisors Guido Münch and Jesse Greenstein, with a thesis on stellar abundances using a Fabry-Perot interferometer at Mount Wilson Observatory. She also holds a B.S. from the University of Arizona in 1978. Following her doctorate, Cohen was a Miller Postdoctoral Fellow at UC Berkeley from 1971 to 1974 and an assistant astronomer at Kitt Peak National Observatory. She joined Caltech as Associate Professor in 1979, was promoted to Professor in 1988, and served as the Page Professor from 2005 until assuming emeritus status in 2018. Additional roles include Executive Officer for Astronomy (1995-1996), Caltech co-chair of the Keck Science Steering Committee, and Caltech representative to AURA. She led the team designing and building the Low Resolution Imaging Spectrograph for the Keck Telescope's first light from 1986 to 1995.

In space science, Cohen's research focuses on near-field cosmology and chemical evolution of galaxies, particularly the Milky Way galaxy's outer halo, globular clusters, and extremely metal-poor stars. She uses high-dispersion, high signal-to-noise ratio spectra from the Keck Telescope for detailed abundance analyses exploring chemical evolution, star formation history, nucleosynthetic processes, light element and helium variations in globular clusters, chemical uniformity in Galaxy and M31 clusters, and early supernovae properties from metal-poor halo stars. Current efforts map the outer halo with RR Lyrae stars. Elected to the National Academy of Sciences in 2017, she was the 2011 Cecilia Payne-Gaposchkin Distinguished Lecturer. Her work has profoundly influenced understanding of Local Group galaxy formation.

Professional Email: jlc@astro.caltech.edu