A previously dormant supermassive black hole in the galaxy SDSS1335+0728, located roughly 300 million light-years from Earth, has stunned astronomers by bursting into life with a series of intensely powerful X-ray eruptions.
Detected first in late 2019 and monitored since by NASA and ESA space telescopes, the object—now dubbed Ansky—is emitting radiation bursts unlike anything previously observed, challenging current astrophysical models.
A Cosmic Awakening Unlike Any Other
Astronomers were first alerted to the awakening of Ansky in late 2019, when it suddenly began emitting unusual X-ray signals. Follow-up observations with NASA’s Swift X-ray space telescope, and later with ESA’s XMM-Newton, Chandra, and other missions, revealed that the once-quiet black hole had entered a highly active phase.
The phenomenon is characterized by quasiperiodic eruptions (QPEs)—short-lived, recurring X-ray flares thought to arise when black holes consume nearby material. But what sets Ansky apart is the sheer scale and intensity of its activity.
Record-breaking Bursts That Defy Expectations
“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 researcher at the Massachusetts Institute of Technology (MIT).
“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.
No Signs Of Stellar Destruction
QPEs are often linked to tidal disruption events, where a black hole tears apart a star and consumes its debris. But that doesn’t appear to be happening here. There are no visible traces of a star being shredded near Ansky, adding further mystery to the event.
“ We thought that QPEs were the result of small celestial objects being captured by much larger ones and spiraling down towards them,” said Erwan Quintin, an X-ray astronomer and research fellow at ESA, he added, “Ansky’s eruptions seem to be telling us a different story.”
A Gravitational Wave Connection?
The unusual behavior of Ansky may be of particular interest to upcoming missions like LISA (Laser Interferometer Space Antenna), a joint ESA/NASA project aiming to detect gravitational waves from space.
“These repetitive bursts are also likely associated with gravitational waves that ESA’s future mission LISA might be able to catch,” Quintin added “It’s crucial to have these X-ray observations that will complement the gravitational wave data and help us solve the puzzling behaviour of massive black holes.”
Pushing The Boundaries Of Black Hole Physics
The intensity, frequency, and longevity of the emissions from Ansky are pushing existing theoretical models to their limits. “This pushes our models to their limits and challenges our existing ideas about how these X-ray flashes are being generated,” Chakraborty noted.
Researchers currently have more models than data and are calling for extended monitoring campaigns to gather the information needed to decode this behavior. The research team’s findings were published in Nature Astronomy in March 2024, providing a crucial stepping stone in our understanding of active galactic nuclei (AGN) and their dynamics.
