Astronomy & Astrophysics
Astronomers Catch a Recurring Black Hole Eruption in Real Time for the First Time
Black holes are famously invisible, but when they feed, they announce themselves. For the first time, astronomers have watched one of these feeding eruptions unfold in real time — a recurring outburst from a supermassive black hole in the galaxy IC 3599, located roughly 280 million light-years from Earth.
An eruption with a rhythm
IC 3599 has flared dramatically three times: in 1990, 2010, and now in 2026. The first two eruptions were only discovered after they had faded, reconstructed from archival data. This third one is different — researchers caught it while it was happening, using XMM-Newton, ESA's X-ray space observatory, to track the event as it evolved. The multiwavelength analysis, posted to the arXiv preprint server on July 10, reveals a strong oscillation pattern in the X-ray light curve, suggesting instability in the disk of material swirling around the black hole.
The cause: a partial tidal disruption
The most likely explanation is a partial tidal disruption event (TDE). A star passing too close to the supermassive black hole is not entirely consumed — instead, the black hole rips off a fraction of the star's material each time it passes, creating a flare that repeats every 16 years or so. This is distinct from a full TDE, where the star is completely destroyed in a single event. Only a handful of such repeating TDE candidates have ever been identified, and IC 3599 is one of the best-documented examples.
Why this matters
Recurring TDEs offer a unique window into the population of dormant supermassive black holes that sit at the centers of most galaxies. Most of the time, these black holes are quiet and nearly impossible to study. A star that is repeatedly stripped of material provides a natural laboratory: each eruption reveals the black hole's mass, spin, and environment. Watching the 2026 eruption in real time allowed astronomers to measure the oscillation period and the rate at which the flare brightened and faded — data that would have been lost if the event had only been reconstructed from archives.
What comes next
The galaxy is now being monitored across multiple wavelengths to see how the outburst evolves. The third flare also confirms the roughly 16-year period, strengthening the case that a single star is on a highly elliptical orbit, losing a bit of mass every time it swings close to the black hole. If the pattern holds, the next eruption should come around 2042 — and astronomers will be ready for it.
— A knowledge brief based on a July 2026 multiwavelength analysis posted to arXiv.