In a quiet expanse of West Virginia hills, the biggest excitement on many days may be the latest news about a new kind of neutron star. Somewhere between Morgantown, W. Va., and Charlottesville, Va., about an hour from the nearest Wal-Mart, world-class astronomers are scanning the radio sky for elusive data that might challenge our current understanding of our galaxy and indeed the entire cosmos. A leader of those galactic detectives, Duncan Lorimer, an assistant professor of physics at West Virginia University, abandons the main campus each summer for a lush and very dark corner of the Appalachian countryside called Green Bank where he works with the world's largest fully steerable dish. There, at the National Radio Astronomy Observatory, he is searching for transient radio sources in the sky. In the fall, he's back on campus sharing his enthusiasm with WVU students, high-school scholars and anyone else who will listen. One recently discovered class of such objects is the rotating radio transients, RRATs or, informally, "rats." "We look for things not seen very often, things that are difficult to detect, and then for only a few milliseconds," Lorimer said one summer evening. "Some will repeat. Some will not." The RRATs hint at more than they actually reveal. "We don't really know much about them," Lorimer said. "That's part of the mystery." This class of neutron stars was identified by their distinctive bursts, unlike other pulsars, which blip away steadily. Lorimer has been studying white dwarfs, neutron stars and black holes, collectively known as "compact objects," since 1991. Most of this research involves looking for and studying neutron stars which are observable with radio telescopes as pulsars. While working as a research associate at the Arecibo observatory, Puerto Rico, the world's largest radio telescope, he met his wife, Maura McLaughlin, then an astronomy graduate student from Cornell, which runs the Arecibo observatory. She is now also an assistant professor of physics at WVU, and they are among the world's top experts on the RRATs, which are thought to be a class of rotating neutron stars. Lorimer titled his proposal for a 2009 Cottrell award "Bursts, Flickers and Cosmic Flashers: Exploring the Transient Radio Sky." The proposal was inspired by a discovery that Lorimer and collaborators made in 2007 while searching archival radio observations for more RRATs. "We were looking at some data taken on the Large and Small Magellanic Clouds, which are satellite galaxies to the Milky Way," he explained, "and quite unexpectedly we detected a very bright burst of radio waves of completely unknown origin." Despite repeated attempts to detect the source again, no further bursts have been seen. He says his observation suggests that this is the prototype of a new class of astronomical objects that could originate from well beyond the Milky Way. Lorimer proposes to search for similar events and try to understand their origin. "One possibility is that they are the radio signals caused by coalescing neutron stars in distant galaxies, but the mystery is far from settled," Lorimer added. Lorimer, born in Darlington, in northeast England, received his Ph.D. studying neutron stars using radio astronomy at the University of Manchester, home of the Jodrell Bank Observatory. He did postdoctoral study at the Max Planck Institute for Radio Astronomy in Germany, and then was a staff scientist at the Arecibo Observatory. He was back at Manchester with a fellowship from the Royal Society when he was part of the team credited with the discovery of the RRATs, which were announced in 2006. "There's a lot of interest in looking for more of these elusive transient radio sources," Lorimer said, and that's what he intends to do as a Cottrell Award winner. The stakes are high. Using telescopes, archives and the latest research tools, Lorimer's work could help probe theories of gravity and general relativity. "It is possible that gravitational wave signals are associated with these transient radio bursts," he said, "and the detection of these could open up a whole new window on the Universe."
Duncan Lorimer's Teaching Plans
Lorimer hopes to prepare students in West Virginia for careers in science by expanding astronomy opportunities for undergraduates, adding more courses and more mentoring and research experiences for students from area high schools. He plans a course called "Explosions in Space," to take up lives and deaths of stars, neutron stars and pulsar astronomy, black holes and the Big Bang. He also hopes to develop curriculum for a new undergraduate major in astronomy, and to initiate collaboration with high schools to promote interest in science and involve students with actual research efforts using data from the Arecibo telescope. In one WVU honors class, he keeps things lively by asking students to imagine being camped on the moon and ponder how often the Earth would rise and set from their vantage point during each day of Earth time. The class also covers topics like extra-solar planets, pulsars, quasars and gamma-ray bursts. "Students complete the class with a real sense of accomplishment," Lorimer says. He also organizes trips for students to the Green Bank, W. Va., telescope and observatory to familiarize them with the technology used in astronomy.