Carolina astronomers capture images of the cosmos
Recent research by physics and astronomy faculty and their labs produced glimpses of the majesty of space.
Objects and events beyond our solar system can be tricky to visualize — and even trickier to understand.
We typically can’t see these objects themselves, just imprints of light that may be hundreds to billions of years old. Some objects don’t produce light at all, including supermassive black holes so dense even light can’t escape.
The difficulties associated with obtaining these rare glimpses of the cosmos make the stories behind them all the more mesmerizing. The UNC College of Arts and Sciences’ physics and astronomy department recently assisted with the capture of several astronomical objects and events that helped us learn more about the nature of our distant universe.
RadioAstron map of quasar OJ 287, showing the larger of the two black holes (bottom), the smaller of the two black holes (center) and a jet flaring out from the smaller black hole (top). (Submitted image)
Seeing double
A team of researchers — including Carolina astronomer and professor Daniel Reichart — captured the first picture of two black holes orbiting each other. The feat is especially remarkable considering a single black hole was photographed for the first time just six years ago.
This pair of black holes makes up quasar OJ 287, the center of a galaxy about 3.5 billion light years from Earth. OJ 287 has stymied observers for over a century with its cyclical pattern of brightening and dimming. Eventually, researchers hypothesized that a pair of black holes could explain the phenomenon. As the smaller one orbits, it disrupts the cloud of gas and dust surrounding the larger one, creating bright flashes of light.
Reichart and colleagues used satellite telescope technology, which can capture clearer images than Earth-based telescopes, to produce an image with enough resolution to see the black holes individually. The approach “achieved a much longer observing baseline, and hence a higher-resolution image” than previous images of black holes, Reichart said.
Members of the Pleiades shine in blue. (Photo by NASA/ESA/AURA/CalTech)
Seven (or more) sisters
A cluster of stars known as the Pleiades has captivated stargazers for millennia, appearing in art, literature and even agriculture guides of many ancient civilizations. Seen in the Northern Hemisphere’s late autumn and early winter, the Pleiades is the only such cluster visible to the naked eye.
But this family of “Seven Sisters” potentially has thousands more siblings, according to a recent study published in The Astrophysical Journal, led by physics and astronomy doctoral student Andrew Boyle and his mentor, professor Andrew Mann, in his lab.
Stars are typically born in groups that drift apart over time, making their lineage difficult to trace. However, Boyle, Mann and their colleagues leveraged the knowledge that stars rotate more slowly as they age to locate other stars likely born at the same time as the Pleiades. Using data from NASA and the European Space Agency, the researchers estimated that the Pleiades is about 20 times larger than previously thought.
“This study changes how we see the Pleiades — not just seven bright stars, but thousands of long-lost siblings scattered across the whole sky,” Boyle said.
This photo from the James Webb Space Telescope shows the host galaxy of GRB 250702B, with the approximate location of the gamma ray burst indicated by tick marks in the inset. (Photo by NASA/ESA/CSA/H. Sears [Rutgers])
Explosion extrapolation
Gamma ray bursts — massive cosmic explosions that happen when a star falls into a black hole — typically last a matter of seconds or minutes, leaving astronomers scrambling to capture them before they burn out. But in June 2025, an unusually long-lived gamma ray burst known as GRB 250702B delighted and puzzled the astronomy community.
The seven-hour event allowed researchers to capture far more data than they have from previous gamma ray bursts, but they also noticed that GRB 250702B was markedly different from other such events. In a recent study published in The Astrophysical Journal Letters, researchers at UNC-Chapel Hill had some possible explanations for the burst’s origin.
“Our analysis shows this event could have several different causes — including the death of a massive star or even a star being ripped apart by a black hole. But we can’t yet tell which explanation is correct,” said Jonathan Carney, a doctoral student working with assistant professor Igor Andreoni in his lab. “In the future, this event will serve as a unique benchmark. When astronomers discover similar explosions, they’ll ask whether they match GRB 250702B’s properties or represent something different entirely.”
Read more about these cosmic discoveries at the College of Arts and Science.
