April 28, 1997

Distinguished astronomer to deliver annual Faculty Research Lecture

By Robert Irion

UCSC faculty members have chosen astronomer Donald E. Osterbrock, one of the campus's most accomplished scientists, to deliver the 31st annual Faculty Research Lecture. The honor, which recognizes outstanding research achievements, is the highest that faculty may bestow upon their colleagues.

Osterbrock will give his talk, "Active Galactic Nuclei: Lighthouses in the Universe," at 8 p.m. Monday, May 12, in the new Music Center Recital Hall. The lecture is free and open to the public. A reception will follow in the Crown College Provost's House.

Osterbrock came to Santa Cruz in 1973 and served as director of Lick Observatory from then until 1981. He is now professor emeritus of astronomy and astrophysics and astronomer emeritus at UC Observatories/Lick Observatory. He maintains an active research program and has gained renown for several recent books on the history of American astronomy.

In selecting Osterbrock, UCSC's Academic Senate cited his "extraordinarily important and influential" contributions to a wide range of disciplines within astronomy. Early in his career, he focused on theoretical models of the internal structure of the sun. This work helped astronomers understand the structures of stars in general and led to the first detailed and satisfactory models of evolved stars, such as red giants and supergiants. His subsequent theoretical work on the sun helped demonstrate why the sun's outer atmosphere is far hotter than its surface.

Osterbrock's midcareer work led to fundamental insights into the nature of gaseous nebulae, gas-filled regions of space between stars that shine--often with striking beauty--as a result of stars embedded in them. Osterbrock used detailed theoretical data on the structures of atoms to explain the likely chemical compositions of the nebulae as well as heating and cooling processes that occur.

His later research, especially after coming to Lick Observatory, explored the extraordinarily powerful nuclei of active galaxies--the subject of his Faculty Research Lecture. As the talk's title implies, active galactic nuclei act as beacons that astronomers can detect across vast reaches of the universe. These objects emit copious amounts of energy at many different wavelengths, from radio waves and X rays to infrared, optical, and ultraviolet light. Frequently, active galaxies propel incredible "jets" of matter and energy from their centers in one or more directions. Research by Osterbrock and others has shown that the most likely sources of such outbursts are disks of dust and gas spiraling into the maws of massive black holes. Indeed, recent studies with the Hubble Space Telescope have strengthened that theory.

Osterbrock's numerous books include a classic research monograph, Astrophysics of Gaseous Nebulae and Active Galactic Nuclei, widely used as a text and reference book in the field. His historical volumes include biographies of astronomer James Keeler and telescope maker George Willis Ritchey, as well as noted reviews of the histories of Yerkes Observatory in Wisconsin and Lick Observatory, which UCSC now operates.

Scientific societies have recognized Osterbrock's career with nearly all of the kudos that an American astronomer can accrue. He is a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and the American Philosophical Society. He has received the Henry Norris Russell Lectureship from the American Astronomical Society and the Catherine Wolfe Bruce Medal from the Astronomical Society of the Pacific, both in honor of lifetime achievement in the field. Most recently, Great Britain's Royal Astronomical Society awarded Osterbrock its 1997 Gold Medal, an honor he will accept in the fall.

Osterbrock's faculty peers at UCSC also noted that he has supervised the work of more than 20 Ph.D. recipients in astronomy, many of whom have gone on to become leaders in research and at observatories. "In summary," the Academic Senate stated, "Professor Osterbrock's contributions to scientific research in a variety of fields, his leadership in the scientific community, and his deep involvement in the educational process have led him to become one of the world's outstanding figures in the field of astronomy in the second half of the 20th century."

Osterbrock earned his B.S., M.S., and Ph.D. at the University of Chicago. Before joining UCSC's faculty, he held positions at Princeton University, Caltech, and the University of Wisconsin. The Ohio State University and the University of Chicago both have granted honorary doctoral degrees to Osterbrock; he will receive a third such degree from another noted institution just four days after delivering his Faculty Research Lecture.

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