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Alumni & FriendsAdam Bolton pauses in his research at his Harvard office. Several globes can be seen in the background. Photo by Christine Pulliam


Galaxies Far, Far Away

At SFSU, Adam Bolton (B.A., '99) envisioned a career teaching high school physics or music. Today he's doing postdoctoral work at the Harvard-Smithsonian Center for Astrophysics, leading a team of astronomers who calculate the physical makeup of galaxies that are billions of trillions miles from Earth.

At 31, Bolton is part of an international collaboration of five astronomers who use the NASA/European Space Agency Hubble Space Telescope.

Albert Einstein's general theory of relativity is central to their work. The theory suggests that light from distant galaxies is deflected or bent on its way to Earth by the gravitational field of massive objects that come between Earth and these galaxies. Through this phenomenon, which astronomers refer to as "gravitational lensing," the light is distorted into an arc or multiple separate images. When two galaxies align, the light from the galaxy behind forms a bull's-eye pattern, or "Einstein ring," around the foreground galaxy.

Bolton's team captures images of Einstein rings to calculate the mass of the foreground galaxies. "We measure each lensing galaxy's brightness, the speed of its stars, and the radius of the Einstein ring that it produces," Bolton says. "We then use these data to sort out the mix of stars and dark matter within the galaxy."

Resulting information about the distribution of dark matter, an invisible form that has not yet been observed directly, tests commonly held ideas about how galaxies are formed. One such idea is that massive galaxies are formed through the merging of smaller galaxies.

Bolton, who received his doctorate in physics from MIT, says his distinguished research began at SFSU. As an undergrad he worked with Professor Adrienne Cool to identify binary star systems in the core of a star cluster already photographed by the Hubble. That partnership has continued through collaboration on scientific papers.

"The Physics and Astronomy Department at SFSU deserves a lot of credit," Bolton says. "The professors are top-notch, generous with their time and eager to involve students in their research."

-- Denize Springer


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