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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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