Student’s project probes black holes, galaxies

A physics student’s research is using scientific crowdsourcing to better understand how black holes form.

Parker Lemke

When examining a galactic structure that could be feeding massive black holes, University of Minnesota physics doctoral student Melanie Galloway turns to an army of online citizen scientists.

They help her scrutinize thousands of images captured from space by telescope, so that her research can probe how black holes and their host galaxies form, Galloway said.

Participants use a scientific crowdsourcing project platform called Zooniverse, which allows them to label the shapes of galaxies pictured on the website.

“They’re shown an image of a galaxy, and then they’re asked questions,” Galloway said. “Is it very smooth? Does it have a feature? Are there spiral arms?”

Then Galloway uses those descriptions to determine if the shapes identified by the citizen scientists relate to whether the galaxy hosts an active black hole at its center, she said.

Galloway’s project is part of a larger research initiative, Galaxy Zoo, which began in 2007 and found unexpected success when close to 150,000 volunteers helped classify the shapes of a million galaxies, said associate physics professor and project contributor Lucy Fortson.

“It just took off by word of mouth,” Fortson said.

Zooniverse, building off Galaxy Zoo’s success, launched in 2009 with the goal of solving other big-data science problems.

Fortson said the site now uses crowdsourcing to help translate ancient Egyptian scraps of papyrus and hunt for planets orbiting distant stars, among other efforts.

For Zooniverse’s current space-themed exhibit, the Bell Museum of Natural History featured the work of University astronomy researchers who have used the platform to investigate topics like lunar water and the Andromeda Galaxy.

“We got to talking with several of the researchers, and this concept of Zooniverse kept popping up — this crowdsourcing of science,” said museum exhibit specialist Jennifer Menken.

The platform has allowed young astronomy scholars, like Galloway, to focus her attention on analytical research, rather than the process of categorizing thousands of space objects, Fortson said.

“We usually keep a galaxy in the system until at least 40 people have classified it,” Galloway said.

Classifying massive black holes

Black holes are areas of space where matter has been so tightly squeezed that gravity has the strength to trap light.

Astronomers believe most galaxies possess central black holes that might have played a part in both galactic creation and the clenching of their star formations, Galloway said.

Though the violent deaths of stars can spawn black holes, those found at the center of galaxies are millions of times more massive than a typical star, Galloway said.

And when those colossal black holes also have gases actively spiraling into them — which is the focus of Galloway’s
research — they are among the most energetic objects in space.

“Those are the ones we call active galactic nuclei,” she said. “They’re creating matter and spitting out tons of radiation.”

Although the spiral arms of some galaxies originate at a small, central point, others branch out from the edge of a bar-shaped structure, Galloway said, which could funnel gas into the black holes.

Galloway specifically studies whether those bar structures correlate with the presence of an active black hole.

The Galaxy Zoo classifications allows for the ability to do larger statistical research between galaxies that have both bar structures and galaxy centers, Fortson said.

So far, Galloway said, her research has found a slight correlation between the two.

Even as she examines data drawn from vast stretches of the universe, Galloway said she still gets sucked into the online platform supporting her work.

“My research does not involve classifying galaxies myself,” she said. “But sometimes I’ll go onto Zooniverse, and I’ll get very caught up in it.”