Bruce Elmegreen was born in Milwaukee and earned his B.S. in physics and astronomy at the University of Wisconsin-Madison. In 1975 he completed his PhD at Princeton University with Lyman Spitzer, Jr., studying the ionization of the local interstellar medium. While a Junior Fellow at Harvard University, he proposed with Charles Lada that ionization from one generation of stars can compress residual gas and form another generation. He followed that with observations of interstellar filaments as further evidence for triggered collapse and proposed the same process on the scale of spiral arms. In 1984, after 6 years on the faculty of Columbia University, Elmegreen joined the staff of IBM Research, where he remains. There he began studies of galactic spirals with his spouse, Debra Meloy Elmegreen of Vassar College, making the first digitized color images of galaxies and examining their symmetries to find spiral modes. He and his coworkers have investigated interstellar compression from turbulence as well as the formation and evolution of different types of star clusters. He has also worked on interstellar pressure, successfully predicting that the inner regions of normal galaxies would be highly molecular and that only the inner parts of dense clouds would be molecular when the metallicity is low, as he observed in dwarf irregular galaxies with a team led by Deidre Hunter of Lowell Observatory. With Debra Elmegreen he observed, classified, and measured irregular features in young galaxies, finding pervasive clumpy structure on galactic scales and proposing it resulted from gravitational processes at high turbulent speeds. They were the first to observe that galaxy disks are thick at high redshift, suggesting this also follows from high turbulence and explaining the old thick disks of today’s galaxies as remnants of early energetics.
Elmegreen’s work on star formation led to discoveries regarding the structure and evolution of galaxies. He observed pervasive hierarchical structure in young stellar regions, discovered that star formation is rapid following turbulence compression and gravitational collapse, and explained the formation of stellar clusters as the densest parts of the hierarchy. He discovered the largest scales for these processes in galaxies spanning a wide range of cosmic time.
Elmegreen has also maintained an active research program at IBM, writing papers and patents on magnetic materials and devices, phase change material structures, piezoelectronic transistors, magnetic levitation traps, and neural network hardware design. He currently co-leads the Materials Discovery program in IBM’s Future of Climate initiative.
Personal Web Page
American Institute of Physics and American Astronomical Society, Dannie Heinemann Prize for Astrophysics, 2001.
Named after him
Other References: Historic
Other References: Scientific
Elmegreen, Bruce G. & Charles J. Lada, “Sequential formation of subgroups in OB associations,” Ap.J. 214, 725-41 (1977).
Elmegreen, Bruce G. & Debra Meloy Elmegreen, “Properties of barred spiral galaxies,” Ap.J. 288, 438-55 (1985).
Elmegreen, Bruce G. & Edith Falgarone, “A Fractal Origin for the Mass Spectrum of Interstellar Clouds,” Ap.J. 471, 816-21 (1996).
Elmegreen, Bruce G. & Yuri N. Efremov, “A Universal Formation Mechanism for Open and Globular Clusters in Turbulent Gas,” Ap.J. 480, 235-45 (1997).
Elmegreen, Bruce G., “Star Formation in a Crossing Time,” Ap.J. 530, 277-81 (2000).
Elmegreen, Bruce G. & John Scalo, “Interstellar Turbulence I: Observations and Processes,” Ann. Rev. Astron. Astrophys. 42, 211-73 (2004).
Scalo, John & Bruce G. Elmegreen, “Interstellar Turbulence II: Implications and Effects,” Ann. Rev. Astron. Astrophys. 42, 275-316 (2004).
Bournaud, Frédéric, Bruce G. Elmegreen, & Debra Meloy Elmegreen, “Rapid Formation of Exponential Disks and Bulges at High Redshift from the Dynamical Evolution of Clump-Cluster and Chain Galaxies,” Ap.J. 670, 237-48 (2007).
Other Works: Popularizations, History, etc.
Elmegreen, Debra Meloy & Bruce Elmegreen, “What puts the spiral in spiral galaxies?” Astronomy 21, no. 9, 1, 34-39 (1993).
Elmegreen, Debra Meloy & Bruce Elmegreen, “Images,” Sky & Telescope 99, no. 5, 54 (2000).
Hunter, Deidre A., Bruce G. Elmegreen, & Philip Masey, “Big Clusters, Tiny Galaxies,” Mercury 32, no. 3, 34 (2003).