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Single-dish and array telescopes perform complementary tasks for astronomers, but merging their strengths is the challenge one student this summer.
Salman Mujahid ’04, an electrical and computer engineering major, hopes to determine which of the three major radioastronomical image processing systems does that job the best.
He is working as an EXCEL Scholar with Lyle Hoffman, professor of physics, and Ismail Jouny, associate professor of electrical and computer engineering. “I took up this project because image processing is part of electrical engineering,” says Mujahid. Even so, he says he has been interested in astronomy since reading Stephen Hawkings’ writings about the universe.
Mujahid was introduced to Hoffman through a course on the use and abuse of science fiction – examining whether stories and television shows such as “Star Trek” contain more science or more fiction.
According to Hoffman, the radiotelescopes with which Mujahid is concerned are built either as a single-dish instrument, with a single, large paraboloidal reflector that directs rays to a single receiver, or as synthesis arrays that correlate the output of many smaller reflectors.
“Single-dish telescopes typically give greater sensitivity to diffuse emission and better velocity resolution, while synthesis arrays give better spacial resolution of the brighter regions,” says Hoffman.
Hoffman mapped the dwarf irregular galaxy DDO 154 at the single-dish Arecibo lab to assess how far the outskirts of its neutral hydrogen disk extend and at the Very Large Array to examine the fine structure filaments and holes of the central part of the disk.
“It would be of interest to merge the single dish and synthesis array data sets to produce a single map that has both high spatial resolution of the brighter portions and high sensitivity to diffuse emissions,” he says.
Mujahid will evaluate the AIPS, AIPS++ and MIRIAD software systems to determine which allows astronomers to best combine the information from both single-dish and array telescopes. Then he will explore ways for reinterpreting the single dish data as if they were output from a synthesis array so that powerful image processing techniques can be applied to them.
Mujahid calls Lafayette “the perfect place for an education.”
“You get personal attention when you want it,” he explains, adding that this makes understanding concepts easier than they would be at a big school and in big classes.
A graduate of Sadiq Public School in Bahawalpur, Pakistan, Mujahid is a peer adviser for the International Students Association, vice president of the Muslim Student Association, and a member of the Physics Club. He plays intramural squash, badminton, and racquetball, and has volunteered with Habitat for Humanity.