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Shining
light on the dark cosmos
Physicist James H. Buckley seeks discoveries on the shape and fate of the universe By Jeanne Erdmann At the start of each spring semester, when he teaches a new class of astronomy students, James H. Buckley, Ph.D., begins with this request: “Raise your hand if you’ve seen the Milky Way.” “It’s amazing how many people go their whole lives without ever seeing that,” says Buckley, associate professor of physics in Arts & Sciences.
Although much of experimental physics is conducted using unimaginably sensitive telescopes and powerful computers, Buckley’s “laboratory” includes Earth’s entire atmosphere. A powerful optical telescope and camera called the Whipple Observatory gamma-ray telescope, located in the Santa Rita Mountains in Arizona, helps Buckley and his colleagues analyze bursts of gamma rays to understand how galaxies are formed. These gamma rays come from several cosmic sources, including the massive black holes at the center of very active galaxies. “Galactic material fuses onto the black hole, and material is shot back out in relativistic jets moving at speeds of as much as 99.98 percent of the speed of light,” explains Buckley, a member of the McDonnell Center for the Space Sciences’ high energy gamma-ray group. “Gamma rays produced in these jets enter the Earth’s atmosphere, creating an avalanche of electromagnetic radiation. Just like a supersonic jet emits a sonic boom, these fast-moving particles produce an electromagnetic shock wave known as Cerenkov radiation. “So if you ask where the wild things are,” he adds, “they’re at the centers of galaxies.” Buckley spoke at the Council for the Advancement of Science Writing’s 40th Annual New Horizons in Science Briefing, hosted Oct. 27-30 by the University and attended by more than 140 science writers and journalism educators from North America. In a session called “In Search of Cosmic Mayhem,” Buckley described his work on two different projects with a curious connection -- both involve gamma rays called terra electron volt (TeV) photons, the highest-energy photons known to science. In one project, Buckley is measuring TeV gamma ray flares from the center of galaxies. The short duration of these flares tells Buckley that he’s probing a small region near the central engine of a massive black hole.
Compton made a critical observation showing that photons could act like particles -- an observation that today helps physicists like Buckley understand the cosmos. In a second experiment -- but using the same technique as the first -- Buckley is using TeV gamma rays to locate dark matter, which may eventually explain where galaxies begin to form. “This could be a smoking-gun signature of dark matter, and it might be the first indication of supersymmetry, which is one of these grand scenarios for unifying the forces of nature,” Buckley says. “At least it’s a more-encompassing theory than what’s been proven at this point.” From the time he was in high school, Buckley knew he wanted to be a physicist. He read science magazines and was captivated by the 1980s television series Cosmos with Carl Sagan. He enrolled at the University of Toledo as an engineering student to give himself a broad, practical background. But it was the impractical side of physics that attracted Buckley the most. “Everybody seems very concerned with productivity,” he says. “For example, ‘What are you making that has practical importance?’ ‘What new widget can you carry around?’ “What really makes us human is our ability to understand our origins and the origin of the universe. To me, that intellectual product is much more valuable.” After earning a doctorate in physics from the University of Chicago in 1994, Buckley performed four years of postdoctoral work at the Harvard-Smithsonian Center for Astrophysics, studying with Trevor Weekes, head of the Whipple scientists. While at the center, Buckley worked on many areas of gamma ray physics. “His best work was on development of an automated data-analysis procedure, leading to the discovery of short flares from active galactic nuclei, observations from supernova, and null detections that have important implications for the theory of cosmic-ray origins,” Weekes says. Golden age of discovery By then, Buckley’s work was highly regarded. In 1997, just before he joined Washington University, Buckley was awarded the 25th International Cosmic Ray Conference Shakati Duggal Award, given every two years to an outstanding physicist under 35 years old. In 1998, Buckley received the Department of Energy’s Outstanding Junior Investigator award.
Buckley credits Israel with serving as a faculty mentor during the difficult and often frustrating process of getting scientific research funded. Israel says Buckley combines technical hardware skill with a broad and deep understanding of astrophysics. “Jim is so capable and so smart,” Israel says. “He has a superb knowledge and understanding of a broad brush of astrophysics, not just the one area he happens to be working on. “At the same time, he is a superb instrumentalist who really knows how to design and build new kinds of instruments that are pushing the state-of-the art, which enables measurements that would not be otherwise possible.” The universe under Buckley’s watchful eye was actually invisible until the last decade. With vast improvements in optical astronomy and better computational measurements, physicists can answer many questions with high precision. “We now know quite a bit about the shape and fate of the universe,” Buckley says. “These are questions I thought would not be answered in my lifetime.” Buckley never strays far from his engineering background. In his lab, he and three graduate students divide their time among data analysis, interpretat ion and hardware development. He is also developing a new type of detector and developing electronics for Veritas, the next generation of the Whipple telescope that will provide 3-D images of TeV photons. Buckley also wants students to enjoy the night sky without light pollution, so he and a few undergraduates are building a small optical observatory at the University’s Tyson Research Center. “I’ve been out there digging ditches, pouring concrete and building the foundation,” he says. “We just put up the dome.” Back on the Hilltop Campus, he built a radio telescope with the help of an undergraduate student. “I actually machined some of the parts,” he says. As one might imagine, not much time is left at the end of Buckley’s day. Time not devoted to cosmic pursuits is spent with his wife, Kathleen Gallagher, and their two children. “I try to keep a couple of fish alive in a marine aquarium,” he says, “but my daughter is 5 and my son is nearly 2. That’s a pretty busy time in your life.” Even though physicists are enjoying the golden age of astronomy, galaxies will likely remain dark and mysterious places through much of Buckley’s lifetime. Still, he has a wish list of cosmic questions. “I’d like to know what the dark matter and what the dark energy are,” he says. “There’s a slim chance that I will contribute to that answer. “Also, it would be great in my lifetime to have a theory that unified gravity with the other forces. I think that would be fantastic. “Grand unification of the fields is something every physicist dreams of.” |
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