Mashpee student makes stellar discoveries

Bates College senior Alicia Soderberg of Mashpee, Mass., has identified nine new supernovae including the most distant one found to date as part of a National Science Foundation program that provides undergraduates with hands-on research experience.

“It’s thrilling to shout across the room ‘I’ve got one!’ when you spot the first supernova during an observing run,” said Soderberg, a math-physics major who was on leave from Bates to participate in the NSF’s Research Experience for Undergraduates program.

As part of a team of astrophysicists working in Hawaii and at the Cerro Tololo Inter-American Observatory in Chile, Soderberg used the Canada-France Hawaii Telescope and the Keck Observatory, both on Mauna Kea, Hawaii, to make the discovery.

Identifying supernovae is a process of elimination. The CFH Telescope takes two digital pictures of the sky three weeks apart. Soderberg compared the two pictures to identify “residuals,” light objects that changed brightness. Based on her knowledge of luminous astronomical objects, Soderberg then distinguished the residuals from other objects in view, such as variable stars, asteroids and active galactic nuclei. She and her team then confirmed her supernovae identifications with the low-resolution spectrograph on the Keck Telescope.

Since research time at large observatories is strictly scheduled, Soderberg’s recommendations on what to look for with the Keck Telescope were key to the discovery. “With research time at the Keck Observatory so limited, you want to make sure that you don’t waste four hours looking for dust,” she said.

The team launched its search for supernovae — bright, dying stars located billions of light years from Earth — in the hope that measuring the light from these stars can help determine whether the expansion of the universe is accelerating or decelerating. Preliminary results imply that the universe is accelerating, not slowing down.

Considering all that could have gone wrong, Soderberg says she felt “tremendous relief” at the discovery of so many supernovae. Bad weather and software glitches routinely upset the best-laid research plans. Working on the project via the Internet with colleagues collecting data across time zones meant “stress, little sleep and lots of junk food,” Soderberg said.

“Discovering supernovae requires one to remain organized and focused for several 20-hour workdays in a row, something Alicia can do as well as any of the team’s scientists,” said Brian Schmidt, astronomer at Australia’s Mount Stromlo and Siding Spring observatories and lead investigator of the supernova discovery team. “Very few students are given opportunities like this. Alicia has made the most of them by proving herself a hard worker, finding her own funding and asking the right questions of the right people.”

With encouragement from Eric Wollman, professor of physics at Bates, Soderberg received her first NSF Research Experience for Undergraduates grant to study at the Harvard-Smithsonian Center for Astrophysics after her sophomore year at Bates, in summer 1997.

Soderberg stayed at Harvard during the first semester of her junior year, studying astrophysics and becoming a resident expert on the computer software used to help identify supernovae. She spent the second semester of her junior year at the Cerro Tololo Inter-American Observatory in Chile developing a short list of possible supernovae to find with the low-resolution spectrograph at the Keck Observatory.

Soderberg’s research will culminate in a Bates honors thesis, but she doesn’t get starry eyed about just supernovae. She also has studied binary stars in globular clusters from Arizona’s Kitt Peak National Observatory and looked for the existence of water in central-belt asteroids from Cornell University’s Arecibo Observatory in Puerto Rico. Before returning to Bates for the second semester of her senior year, she received another grant — this one from the U.S. Department of Energy — to study gamma ray bursts at Los Alamos National Laboratory in New Mexico.

Soderberg, a graduate of Falmouth High School, is the daughter of Jon and Nancy Soderberg, 726 Old Barnstable Road, Mashpee.

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