UNC Asheville Receives $591,352 National Science Foundation Grant;
Funds to be Used to Build Interferometer at PARI

In 1986, Brian Dennison was just a young astrophysicist when he and a team of scientists discovered a very rare interstellar phenomenon. This phenomenon, known as an extreme scattering event, has been seen only about a dozen times since then. Now a seasoned scientist and UNC Asheville’s first Glaxo-Wellcome Distinguished Professor in Undergraduate Science Research, Dennison and his research team were recently awarded a $591,352 National Science Foundation grant to build equipment to better observe these events. It is the largest National Science Foundation grant in UNC Asheville’s history.

Partnering for this project will be the Pisgah Astronomical Research and Science Education Center (PARSEC) and the Pisgah Astronomical Research Institute (PARI). PARSEC is a UNC systemwide research center, with UNC Asheville serving as the administrative center. PARI, based at a former NASA satellite tracing facility and Defense Department listening post in Transylvania County, operates radio and optical telescopes. The unique site allows for quality faculty research as well as research opportunities for the 200,000 students in the 16-campus UNC system through PARSEC.

The research team for the project includes Chuck Bennett, UNC Asheville physics professor and interim PARSEC director; Ronald M. Blake, PARI research associate; Randy Booker, UNC Asheville Physics Department chair and professor; Michael W. Castelaz, PARI director of astronomical studies and education; Wayne Christiansen, UNC Chapel Hill physics professor and director of the Morehead Observatory; Donald Cline, PARI president; Jose D’Arruda, UNC Pembroke physics professor; David Jauncey, research scientist at the Commonwealth Scientific and Industrial Research Organization, Australia; Joseph Lazio, Naval Research Lab radio astronomer; David Moffett, Furman University assistant professor of physics; and Barney Rickett, University of California-San Diego professor emeritus.

The project centers around two radio telescopes at PARI that can “see” farther into the galaxy than optical telescopes. Dennison, other scientists and students will spend three years linking these two powerful telescopes together through a supercomputer to create a complex piece of equipment called an interferometer.

“In effect, we’ll be creating a giant antenna approximately 300 meters wide,” said Castelaz. “We’ll install identical radio receivers on both of PARI’s 26-meter radio telescopes. The signals from each telescope will be combined in the PARI control room so that the two radio telescopes act as one antenna. In this way, we can observe finer detail and gather much more information about the signals we will be receiving from the depths of space.”

Once completed, the interferometer will allow scientists to monitor some 150 quasars for irregularities that signal an extreme scattering event.

“We’ll be looking at sources in the sky that should have a moderately constant brightness, but because of variation in the interstellar medium – such as gases or clouds – the variations can cause changes in the brightness. Extreme scattering events are remarkable changes in brightness. By studying these changes, we hope to deduce the properties of the interstellar medium that causes the scattering events,” said Bennett.

“Scientists know that fluxuations of gas density in our galaxy cause extreme scattering events,” said Dennison. “But what we don’t know is why they are happening, the nature of the gases or even exactly what causes them. An interferometer is by far the best way to observe extreme scattering events and to possibly learn more about them.”

PARI will be the only place in the world where so many quasars will be observed for a dedicated period of time to monitor for extreme scattering events, Dennison said. When an extreme scattering event is detected at PARI, a call will go out to other observatories worldwide to tune into the event to learn more. Because extreme scattering events take place over a period of several months, many observatories will be able to participate in the study.

The project will provide a tremendous opportunity for students. “One of the greatest benefits of the project will be engaging students in hands-on experiences in radio astronomy,” Dennison said. Students will be involved with the building of the interferometer as well as the observations when they begin.

Bennett agrees. “At PARI students are exposed to all levels of both the development and use of instrumentation, which is especially the case with the interferometer. Such an experience is very unusual even for graduate students. For undergrads to participate at this level is certainly unique,” said Bennett.

“There are just a few institutions where undergraduates can get such an exposure to radio astronomical instrumentation of this caliber,” said Dennison. “Whether these students go into astrophysics or another field, it is a valuable experience.”

Media Contacts:

• Dr. Brian Dennison, UNC Asheville Glaxo-Wellcome Professor, 828/252-5036
• Jill Yarnall, UNC Asheville Public Information Assistant Director, 828/251-6526