A Starry Collaboration

From left, Gillian Knapp, Ed Turner and Michael Strauss, all of the Department of Astronomical Sciences at Princeton.

Princeton and Japanese astronomers collaborate to discover distant galaxies.

By Wendy Plump

Nearly 40 years ago, during the summer of 1980, a Princeton University astrophysicist published a theoretical paper on galaxy formation. On the other side of the world, at nearly the same moment, an astrophysicist from Hokkaido University in Japan published a similar report. As chance would have it, both papers were non-starters, and their theories on formative intergalactic explosions were discarded. But the relationship that evolved between the authors – Jerry Ostriker, an esteemed theoretical astrophysicist, and Satoru Ikeuchi, one of Japan’s foremost physicists and public intellectuals – begot a star-crossed alliance between Princeton and Japanese astronomers that has echoed down through the decades.

In fact it could be said that Princeton’s leading astronomical projects, such as the Sloan Digital Sky Survey (SDSS), the SEEDS exoplanet survey, the CHARIS spectrograph instrument, NASA’s nascent WFirst project and the recent choice of the University of Tokyo as one of Princeton’s strategic global partners, originated in part from the goodwill between two physicists.

“Those papers turned from a scientific story into a personal one when Jerry invited Satoru Ikeuchi, then a young theorist, to come and spend some time at Princeton,” says Edwin Turner, a professor of astrophysical sciences and director of the Council for International Teaching and Research at Princeton. “They were both very broad in their approach, so they talked about a lot of ideas. And each one led to another, and now we have undergraduates and graduates going back and forth and multiple departments working together. What was once ‘a professor here and a professor there’ is now an institution-level partnership, and has been for many years.”

Turner ought to know. By all accounts, his enthusiasm had a great deal to do with carrying the collaboration forward. A young professor of astrophysics when Ostriker first struck up contact with Hokkaido, Turner was part of the cooperative scaffolding. He spent a vivid week “touristing” in Japan in 1986, and found himself transfixed by the culture. He has been working collaboratively with Japanese astronomers ever since.

The relationship with Japanese astronomers, Turner adds, has been one of the most fruitful for the astrophysics department.

The Sloan Digital Sky Survey (SDSS) is but one example of its success. The brainchild of Princeton astrophysicist Jim Gunn, the SDSS was a sweeping survey of the heavens that collected enormous amounts of data. Unfortunately, the costs of the project were astronomical. Princeton needed a partner to help fund it. Quite serendipitously, the National Astronomical Observatory of Japan was simultaneously siting the Subaru 8.2-meter infrared telescope atop Mauna Kea in Hawaii. With a price tag of about $400 million, it would become the world’s most expensive, most advanced wide-view telescope. Japan had the funding but needed young astronomers with the expertise to exploit Subaru’s capabilities. A plan was hatched, and a pact was struck: formally, a Memorandum of Understanding – in which the newly formed Japan Participation Group (JPG) provided partial funding for SDSS and then sent a cohort of astronomers to Princeton to learn from its observational astronomers. At that point, it was astronomy’s largest ever formal, integrated international collaboration.

Gillian Knapp, emerita professor of astrophysical sciences at Princeton, remembers the excitement of the period well.

“Given that SDSS was designed from scratch, we collaborated on hardware, advising, designing and fundraising,” she says. “It was one of the first projects you might call holistic in that the science was all being thought out together.”

Asked how she and the other faculty at Princeton handled the Japanese work gestalt, Knapp, who is British, laughed. “I wouldn’t dream of being able to understand either the Japanese, or for that matter, the U.S. way of thinking. But I do think that the Japanese ethos of politeness and of treating each other with respect went a very long way.”

More recently, the memorandum has expanded to include additional collaborative programs: the CHARIS project, the Prime Focus Spectograph or PFS, and NASA’s upcoming WFirst project. A team of Princeton researchers led by Princeton professor N. Jeremy Kasdin, for example, has designed and built an instrument for CHARIS that will allow Subaru to make direct observations of planets orbiting nearby stars. And on the horizon is WFirs, which is dedicated to exoplanet detection and dark energy research. While many institutions are involved in these projects, Princeton is a key partner.

Michael Strauss, professor and associate chair of the Department of Astrophysical Sciences, says none of this would likely have happened without the relationship between Princeton and Japanese astronomers.

“Subaru is really unique at the moment, and so the data we’ve gathered are unprecedented,” he explains. “What are we doing with this science? Looking for some of the most distant galaxies and quasars in the universe. Looking at very distant objects and what they were like soon after the Big Bang. Studying the structure of our own Milky Way galaxy, and asking fundamental questions about what the nature of galaxy formation was.

“The universe is a very big place, and we are, in a sense, just at the beginning of a grand project to map it,” he adds. “Princeton has a reputation in astrophysics, and this continues to burnish it. And our students are definitely involved – undergrads, post-docs, graduate students. They are making discoveries of their own.”

PHOTO: Ben Weldon