Undergraduate Astronomer Helps the World To See "Invisible" Light from Star Clusters

When Blair Porterfield outgrew her local summer-camp options at age 14, her father suggested an astronomy camp at the University of Arizona. "I'm not sure why he wanted me to go," Porterfield mused. "I hadn't been interested in science at all up until that point."

In a case of "father knows best," astronomy camp couldn't have been a more perfect choice. "After the first camp, I was absolutely hooked," said Porterfield. "As soon as I got back home, I knew I wanted to be an astronomer. I knew what I wanted to do with my life." She returned to the camp three more times, and each time her love for astronomy grew stronger.

By the time she turned 16 -- the age at which she was expected to find a part-time job -- Porterfield knew that only an astronomy-related job would suit her. She contacted family friend and Penn State Professor of Astronomy and Astrophysics Mercedes Richards. Richards told her about an opportunity with NASA's Swift satellite, whose science and flight operations are controlled by Penn State from the Mission Operations Center in State College, Pennsylvania.

Porterfield jumped at the opportunity. "The thought of being there when a gamma-ray burst goes off, and knowing about it before anybody else was so exciting to me," she explained. Even when the work she was assigned wasn't so dramatic, her enthusiasm didn't wane. "I started out doing data mining," Porterfield recalled. "It was pretty simple stuff. I hadn't taken physics or calculus yet, and without that knowledge there wasn't much I could do scientifically."

But she's come a long way in her six years on the job. Now a Penn State senior majoring in Astronomy and Astrophysics, Porterfield has collaborated on major research projects, and has co-authored nine published research papers. Most recently, she's been working with Penn State Research Associate Michael Siegel, who leads the Swift Ultraviolet/Optical Telescope (UVOT) team. They've been using the data captured by the UVOT to study the light emitted by star clusters. Some of the results of their work recently were released in the form of a huge online image gallery -- a collection of some of the best pictures ever taken by the UVOT, including some very early images that had never before been published.

NGC 2539 is an open star cluster located about 4,400 light-years away in the constellation Puppis. At 370 million years old, it is a relative youngster. This false-color ultraviolet image, which reveals some of the youngest and hottest members in the cluster, is a composite from Swift's ultraviolet filters (uvw1, uvm2 and uvw2). Credit: NASA/Swift/B. Porterfield, PSU

"My job was to make visual representations of what these star clusters might look like if we could actually see them," Porterfield explained. "We can't actually see anything in the ultraviolet, but using the data from these star-cluster studies, we can assign a visible-light color to each of the three UV filters aboard Swift." This process of matching visible-light colors with UV wavelengths emitted by the star cluster produces a "false color" image -- an image that approximates how the star cluster looks to the telescope in a way that the human eye can see.

"Blair proved to have a flair for making color images from the UV data, so I just handed it over and let her run with it," explained Siegel. "One of the most satisfying things about working with students is watching their progress. When Blair first worked for us, we mainly assigned her repetitive but straight-forward data analysis. Now she's doing more complex work and coming up with ideas and insights of her own."

With graduation looming large, Porterfield is contemplating what comes next in her astronomy career. "I'm interested in getting a job as a telescope operator, although I don't necessarily have a particular observatory in mind," she said. "Any observatory would be pretty cool."