Arjun Dey is an astronomer at the National Optical Astronomy Observatory, where he studies how galaxies form and evolve and how they trace the large-scale distribution of matter in the universe. He aims to apply massively multiplexed spectroscopic capabilities to the solution of major astrophysical mysteries, such as our cosmological origins and the nature of dark energy. In the current paradigm of galaxy formation, the most massive galaxies form at the nexus of large filaments of gas and dark matter. While at Radcliffe, Dey is searching for evidence of filamentary flows into regions where massive galaxies are forming and mapping the associated dark matter distribution. Dey was born in India. He received his BA from Northwestern University and a PhD in astronomy from the University of California, Berkeley. He was an NOAO postdoctoral fellow and then a Hubble Postdoctoral Fellow at the Johns Hopkins University before joining the scientific staff of the National Optical Astronomy Observatory in Tucson, Arizona. Dey is committed to representing the needs of the astronomical community to federal funding agencies (the Department of Energy, NASA, and the National Science Foundation) and has served on advisory committees such as the NASA Advisory Council’s Astrophysics Subcommittee.