Title: Ansky Awakens: A Supermassive Black Hole Comes to Life in Real-Time
For ages, black holes have been amongst the most puzzling entities in the universe. These immense gravitational forces, especially the supermassive ones nestled in galactic centers, are often challenging to observe directly because of their embedded darkness and vast distances. Nonetheless, astronomical equipment worldwide has now recorded something remarkable: a once-dormant black hole, situated 300 million light-years away in a galaxy known as SDSS1335+0728, has stirred from a multi-decade slumber—illuminating the sky and enhancing our comprehension of black hole activities.
Named “Ansky,” this recently active black hole is presenting a rare and priceless chance for scientists to witness the precise moment a supermassive black hole “activates,” transforming into what is termed an active galactic nucleus (AGN).
From Inactivity to Intensity
Contrary to the fearsome space beasts depicted in fiction, black holes do not behave that way. In reality, numerous black holes spend extended intervals in a quiescent state, hardly interacting with their environment. That was the situation for the black hole in SDSS1335+0728—until late 2019.
During that year, astronomers observing the relatively nondescript galaxy realized that its nucleus had unexpectedly brightened in optical images. This led to a series of follow-up evaluations, including data collected by NASA’s Swift space telescope and the European eROSITA X-ray telescope. Initially, however, no X-ray emissions were found—leaving researchers intrigued yet cautious.
Then, in February 2024, the black hole made a dramatic return, emitting surprising and intense bursts of X-rays at almost regular intervals. These flares signified its emergence as a phenomenon known as a quasiperiodic eruption, or QPE.
What Are QPEs?
QPEs are transient, intense flashes of X-ray radiation originating from the area around supermassive black holes. Discovered in 2019, they have only been documented a few times since. The causes of QPEs remain enigmatic, making each new instance, such as Ansky’s, vital for improving our theoretical frameworks.
Lorena Hernández-García, the principal researcher from Valparaiso University in Chile, states, “This rare occurrence allows astronomers to monitor a black hole’s behavior in real-time.” Equipped with space-based observatories like ESA’s XMM-Newton and NASA’s NICER, Chandra, and Swift, the team is diligently observing the captivating light display.
A Black Hole Unlike Any Other
Ansky’s uniqueness lies not merely in its flares but in their nature. “The X-ray flashes from Ansky last ten times longer and are ten times more brilliant than what we observe in an average QPE,” notes Joheen Chakraborty, a PhD candidate at MIT and a member of the research team.
The X-ray bursts from Ansky occur on a cycle of about 4.5 days—a frequency significantly longer than those seen in other known QPEs. Each eruption releases 100 times more energy than other comparable sources. These features are challenging existing theories and prompting astrophysicists to reconsider how such flares can arise.
Theories Under Scrutiny
Historically, QPEs have been linked to the tidal disruption of stars—spectacular phenomena in which stars venture too close to a black hole and are torn apart, creating a luminous accretion disc of rotating matter. However, Ansky does not exhibit the definitive signs of having consumed a star.
Alternative theories are now being explored. One hypothesis proposes that the accretion disc may consist not of fragmented stellar debris but of interstellar gas that the black hole has begun to draw in from its galactic surroundings. In this scenario, a smaller entity—such as a compact star or a smaller black hole—could periodically disrupt the disc, triggering the bursts of radiation.
Learning from Light and Beyond
The exceptional sensitivity of the XMM-Newton space telescope has been crucial in gauging how Ansky’s brightness varies between bursts, enabling scientists to assess the energy output. These findings are essential for comprehending the mechanisms involved.
Erwan Quintin, a researcher at the European Space Agency, remarks, “For QPEs, we are still at a stage where we possess more models than data. We require additional observations to decode the situation.” Monitoring Ansky not only offers fresh data but also opens up new avenues—such as detecting gravitational waves associated with these enigmatic outbursts.
A Future with LISA
The European Space Agency’s imminent mission LISA (Laser Interferometer Space Antenna), crafted to identify gravitational waves originating from cosmic occurrences, may play a crucial role in this investigation. If QPEs indeed involve compact objects colliding or merging, the signals generated from these events should be detectable by instruments like L.