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Faculty Profile: Brent Tully

by Bob Joseph, Faculty Chair

Brent Tully

Brent Tully is one of the fathers of modern observational cosmology. With his colleague, Richard Fisher, he established the relation between the luminosities of spiral galaxies and the width of the 21-cm hydrogen emission line. This "Tully-Fisher relation" provides a powerful technique for measuring distances to galaxies, the measurement essential to understanding the large-scale structure of the Universe.

Tully has gone on to use this technique to study the expansion rate of the Universe and the distribution of so-called "dark matter" on the enormous spatial scales of superclusters of galaxies. The Institute's cosmic geographer, he probably knows more than anyone else about the contents and structure of the local Universe out to distances beyond 100 million light-years. Over many years, he has systematically assembled information about the properties of galaxies in the local Universe. Cambridge University Press published this data in the Nearby Galaxies Atlas (1987) and the Nearby Galaxies Catalog (1988).

More recently, Tully has been interested in using his detailed inventory of the local Universe for public education. Teaming up with television producers and supercomputer experts, he developed software that allows the viewer to take a virtual tour through the local universe. Go to his Web page,, to manipulate a data cube with 30,000 galaxies. Tully was also a science advisor for the PBS Nova program "Runaway Universe," and he is science advisor for the PBS documentary What's Up in the Universe?

Tully has been honored as a distinguished alumnus of the University of Maryland. In November 2003, a group of astronomers gathered near Sydney, Australia, to celebrate his sixtieth birthday with a conference entitled "Structure and Dynamics in the Local Universe." He is one of the five IfA astronomers recognized as being among the world's most cited and influential researchers in the space sciences.

Tully was born in Toronto, Canada. He did his undergraduate work at the University of British Columbia and then emigrated to the United States to study for his PhD at the University of Maryland. After a postdoctoral position in France, he joined the faculty of the IfA and has remained here for 30 years.

At the IfA, Tully is known for finding interesting places to take sabbaticals, including Paris, Bologna, Groningen, Santa Cruz, Berkeley, Chile, Melbourne, and Nice. He is also an enthusiastic party-giver who holds an IfA party at his beachfront home to begin each academic year.