A supermassive black hole that scientists have nicknamed “Ansky” has awakened after a long dormant period, and is now emitting powerful X-ray flares from across deep space.
Most galaxies have a supermassive black hole at their center that is millions of times the mass of the Sun. However, long cycles of feeding and rest leave them in inactive states that make them difficult to spot. Nestled in the Virgo constellation, a galaxy 300 million light years from Earth, designated SDSS1335+0728, hosts the Ansky black hole, which has been silent for decades.
Ansky Awakens
Scientists first detected hints of Ansky reawakening at the end of 2019 as the galaxy suddenly increased in brilliance. Years of research led astronomers to hypothesize that the galactic changes resulted from the awakening of the black hole.
“When we first saw Ansky light up in optical images, we triggered follow-up observations using NASA’s Swift X-ray space telescope, and we checked archived data from the eROSITA X-ray telescope, but at the time we didn’t see any evidence of X-ray emissions,” said Paula Sánchez Sáez, a researcher at the European Southern Observatory, Germany, and leader of the team that first explored the black hole’s activation.
Supermassive Black Hole X-Rays
X-ray bursts from Ansky were later identified by a team led by Dr. Lorena Hernández-García of Valparaíso University in Chile. The team utilized data from the European Space Agency’s XMM-Newton X-ray telescope and NASA’s NICER, Chandra, and Swift observatories. As Ansky reawakened, the team observed quasiperiodic eruptions (QPEs)—a pattern of repeated X-ray bursts.
“The first QPE episode was discovered in 2019, and since then we’ve only detected a handful more. We don’t yet understand what causes them. Studying Ansky will help us to better understand black holes and how they evolve,” said Hernández-García.
“XMM-Newton played a pivotal role in our study. It is the only X-ray telescope sensitive enough to detect the fainter X-ray background light between the bursts,” Hernández-García added. “With XMM-Newton we could measure how dim Ansky gets, which enabled us to calculate how much energy Ansky releases when it lights up and starts flashing.”
QPEs Explained
When matter drifts too close to the edge of a black hole, it is pulled in and torn apart, forming an accretion disk—a hot, rapidly spinning ring of matter resembling water spiraling down a drain. Scientists typically associate QPEs with stars or small black holes disturbing these disks. However, in Ansky’s case, no evidence suggests that a star was consumed.
Due to its unusual behavior, researchers are exploring alternative explanations. One leading theory is that gas, rather than a star, formed the accretion disk, and that the X-ray flares result from a small object repeatedly disturbing this swirling matter.
“The bursts of X-rays from Ansky are ten times longer and ten times more luminous than what we see from a typical QPE,” said Joheen Chakraborty, a team member and PhD student at the Massachusetts Institute of Technology.
“Each of these eruptions is releasing a hundred times more energy than we have seen elsewhere. Ansky’s eruptions also show the longest cadence ever observed, of about 4.5 days. This pushes our models to their limits and challenges our existing ideas about how these X-ray flashes are being generated,” Chakraborty continued.
A Unique Opportunity
Ansky presents astronomers with a rare opportunity to observe black hole evolution in real time, which may help unravel the mechanisms behind QPEs and other high-energy phenomena.
“For QPEs, we’re still at the point where we have more models than data, and we need more observations to understand what’s happening,” said ESA Research Fellow and X-ray astronomer Erwan Quintin.
“We thought that QPEs were the result of small celestial objects being captured by much larger ones and spiraling down towards them. Ansky’s eruptions seem to be telling us a different story. These repetitive bursts are also likely associated with gravitational waves that ESA’s future mission LISA might be able to catch.”
Studying X-ray emissions now will be essential for comparing with future gravitational wave observations, helping scientists decode the complex behaviors of black holes.
The paper “Discovery of Extreme Quasi-periodic Eruptions in a Newly Accreting Massive Black Hole” appeared on April 11, 2025, in Nature Astronomy.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.