Honors Summer Research scholar searches Milky Way for celestial objects

Alicia Wooten ’17 and physics professor Scott Hyman work in the Guion lab, where Wooten is scouring the center of the Milky Way for her Honors Summer Research Program.
Alicia Wooten ’17 and Professor Scott Hyman work in the Guion lab, where Wooten is scouring the center of the Milky Way for her Honors Summer Research Program.

Space. Ever since Alicia Wooten ’17 was little, she’s felt its inexorable pull.

On a recent summer afternoon, it draws her to a lab in Guion’s basement. Wooten peers deep into the Milky Way, searching the galactic center for celestial bodies via digital images captured by radio telescopes in New Mexico. Down the left side of one computer screen, a list of numbers catalogs the images in the batch she is examining. The rest of the screen displays to the untrained eye a mottled, fuzzy field of gray.

Wooten is six weeks into her Sweet Briar Honors Summer Research Program project and starting to get nervous about having to explain her research to her HSRP colleagues in July. It’s no wonder — it’s pretty mind-bending stuff.

In short, she and her faculty advisor, professor of physics Scott Hyman, hope the weekly observations they receive from the Jansky Very Large Array will reveal new characteristics about known objects in space or, even better, previously unidentified objects. Once converted to an image, they can detect and study naturally radio-emitting objects in the Milky Way.

Wooten and Hyman are specifically looking for “transient” sources of radio emissions — objects that suddenly change from a quiescent, undetectable mode into a highly energetic state. That makes their job harder, of course. The timescales of the intense emission can be from minutes to months, and unless the object is emitting when the telescope array is looking at it, it goes undetected.

The Karl G. Jansky Very Large Array consists of 27 230-ton dish antennas that together comprise a single radio telescope system. Image courtesy of NRAO/AUI and NRAO.
The Karl G. Jansky Very Large Array consists of 27 dish antennas that together comprise a single radio telescope system. Courtesy of NRAO/AUI and NRAO.

Wooten is able to access the data within hours after each observation. If she finds something, she and Hyman will alert the National Radio Astronomy Observatory, which operates the Jansky VLA. Then, operators can point the array toward that spot in the galaxy to make more detailed observations in order to better understand the nature of the transient emitting object.

“Basically, we’re looking for things that go boom in the night,” Hyman says. “They’re always there, they’re just in a dormant state.”

Wooten, a math and physics major from Columbia, Md., says she wanted to work with Hyman on his research because space is, well, cool.

And, she admits, she’s a “massive sci-fi dork” and devotee of the “Stargate” sci-fi TV franchise.

“I noticed it’s always the astrophysicist who saves the day,” she says. “That made me decide to take Dr. Hyman’s intro astronomy and astrophysics course last fall. I really enjoyed it, so when he told me about his research interests, I wanted to get involved.”

Finding a new transient is a bit of a long shot, but Hyman and his students have done it before. In 2004, they observed bursts of radio energy of a type never seen before. The discovery suggested that its source could be a new class of astronomical objects, or a different kind of emission from a known source, such as a pulsar or brown dwarf star. Their work was published in the journal Nature.

So far this summer, the NRAO has made seven observations. When there isn’t new data to analyze, as on this day, Wooten pours over archival images.

She is learning the ropes, but also recording information from what she observes for further analysis.

“I feel like maybe I could read an ultrasound now,” she says.

On Wooten’s screen, green pinpoints of light mark locations of previously identified objects, many too faint to see on the low-resolution, low-sensitivity rendering of the image. Something large and bright is there, too, an irregular patch of white against the gray. Hyman thinks it could be the Mouse, a known remnant from an exploded star known as a supernova.

To Wooten’s right, a second laptop displays the spreadsheet she’s been adding to for weeks. When she sees what she believes is a source, she measures the object’s size, and records its intensity, spectrum and location. These results can be compared to other’s observations of the same object taken previously at different frequencies. Wooten and Hyman are looking at images made from 330 MHz frequency (90-centimeter wavelength) observations.

While finding a transient is the ultimate prize, another goal of the summer’s work is to learn as much they can about the crowded center of the galaxy.In recent years, low-frequency imaging has yielded greater resolution and sensitivity leading to the detection of new characteristics of known sources and the discovery of new ones.

Reduce-Noise-1075
Wooten’s project involves a lot of screen time.

In her project description, Wooten explains that radio waves have a longer wavelength than visible light. Studying them allows astronomers to observe phenomena that may not be seen in other portions of the electromagnetic spectrum.

This is her first foray into radio astronomy and it hasn’t disappointed.

“To have the chance to not only learn about radio astronomy, but to get hands-on experience in the field is extraordinary,” Wooten says.

Participating in summer honors offers benefits apart the project itself. There’s one-on-one collaboration with faculty, and interaction with other students and faculty advisors, who form a tight-knit group over the eight weeks.

“It has been really interesting to not only get to delve deeply into my own interest, but to get to learn about the passions of some of my peers,” Wooten says. “As a double STEM major, I don’t get the chance to get out of Guion very much. The program’s weekly lectures have been a fun way for me to learn about subjects I wouldn’t have otherwise been exposed to.”

Her research is valuable, too, because she wants to get her Ph.D. and work for NASA someday. Meanwhile, college isn’t all math equations and “Stargate” reruns. Wooten returned to Sweet Briar last year because it feels like home to her, she says. She couldn’t wait to rejoin her soccer teammates and coaches.

She’s also treasurer of her class and the Vixen Comic Book Club, a member of the ballroom dance club, president of Tau Phi and a member of Falls on Nose.

If spending eight hours a day for eight weeks this summer staring at a computer screen seems like a tough transition, Wooten smiles and says, no.

“I think it all boils down to: Space is cool.”