In the dark heart of galaxies, supermassive black holes lurk like cosmic predators. When an unsuspecting star strays too close, the result is both violent and spectacular. The star is torn apart by the black hole’s immense gravity, its gas and dust stretched into ribbons of light and energy in an event known as a tidal disruption event, or TDE.
Astronomers have long studied these celestial catastrophes, but a strange twist has emerged: sometimes the real fireworks are delayed. One particular case, WTP 14adeqka, has now captured the scientific spotlight. A decade after its discovery, this star’s death is still sending signals across the cosmos—radio waves that continue to puzzle and enlighten astronomers.
Discovering WTP 14adeqka
The story begins in 2015, when NASA’s Wide-field Infrared Survey Explorer (WISE) spotted an unusual flare of mid-infrared light. The source was later identified as a TDE at a relatively nearby redshift of 0.019—meaning its light had traveled about 250 million years before reaching Earth.
At first, WTP 14adeqka seemed like just another addition to the growing catalog of tidal disruption events. It shone brightly in the mid-infrared, peaking two years later with a staggering luminosity of 10 tredecillion erg per second—a number so large it defies imagination. But astronomers soon realized this was no ordinary event.
The Mystery of Delayed Radio Emission
When a TDE occurs, astronomers often look for radio signals—the faint “whispers” of matter being blasted outward from the black hole. These signals are produced by synchrotron emission, where charged particles spiral around magnetic fields at nearly the speed of light.
But in many cases, including WTP 14adeqka, the radio light show doesn’t begin right away. Instead, it appears years later. For WTP 14adeqka, radio waves began rising about four years after the initial discovery, peaked 2.5 years later, and remain bright even in 2025.
Why the delay? Astronomers have debated several possibilities: perhaps the radio jets are aimed away from us (off-axis jets), or maybe the black hole ejects material only after a long pause. Another explanation is that the surrounding environment—dense gas and dust near the black hole—slows down the visible onset of radio activity.
A Decade of Watching the Echoes
A team led by Walter W. Golay at the Harvard-Smithsonian Center for Astrophysics has now provided the clearest picture yet. Using the Very Large Array (VLA) and the Very Long Baseline Array (VLBA), they monitored WTP 14adeqka for nearly a decade. Their results, published on August 22, reveal just how powerful this delayed radio outflow really is.
The radio glow from WTP 14adeqka carries an energy of about 500 quindecillion erg—an almost unimaginable amount of power. The emission region measures about 0.2 light-years across, with a magnetic field strength of 0.12 Gauss (roughly twice the strength of Earth’s magnetic field). The peak radio frequency sits steadily at 2.0 GHz, showing only mild fading over time.
These precise measurements paint a picture of a compact, energetic outflow expanding into space. But crucially, the observations also rule out one possibility: the signal cannot be explained by a promptly launched off-axis jet. Something else—perhaps a delayed, quasi-spherical outflow—is at work.
Why This Matters
This discovery changes the way astronomers think about black hole feasts. WTP 14adeqka is the first mid-infrared TDE with confirmed delayed radio emission, proving that such events can launch powerful outflows years after the initial star is shredded.
This finding also suggests that TDEs are more complex than once believed. They are not just one-time cosmic explosions, but multi-stage dramas that can unfold for years, even decades. Studying them in radio light allows scientists to see past the blinding glare of the initial flare and into the hidden physics of how black holes interact with their surroundings.
The Human Dimension of Discovery
Though the numbers are staggering and the physics subtle, there is something profoundly human in this pursuit. Astronomers spent years patiently listening for whispers of radio light from an event that occurred hundreds of millions of years ago. It is a testament to our species’ curiosity that we can take instruments on Earth, point them at the heavens, and reconstruct the death of a star in exquisite detail.
WTP 14adeqka is more than just data—it is a cosmic story. A star lived, wandered too close to a black hole, was ripped apart, and now, years later, its dying echoes reach across the void, telling us secrets about gravity, matter, and the strange engines that power galaxies.
The Road Ahead
As Golay and his colleagues emphasize, this is just the beginning. If one mid-infrared TDE can produce such a delayed radio glow, how many others might behave the same way? Ongoing surveys and radio monitoring campaigns may reveal whether WTP 14adeqka is unique or part of a broader, hidden pattern.
The answers will not only deepen our understanding of black holes, but also refine our knowledge of the environments in which they dwell. Each discovery is a step toward answering one of astronomy’s biggest questions: how do supermassive black holes shape the galaxies that host them?
For now, WTP 14adeqka continues to shine in radio light, a lingering echo of a star’s violent death. And astronomers, like cosmic detectives, will keep listening—knowing that every faint signal carries the story of a universe still unfolding before our eyes.
More information: Walter W. Golay et al, Radio Emission from the Infrared Tidal Disruption Event WTP14adeqka: The First Directly Resolved Delayed Outflow from a TDE, arXiv (2025). DOI: 10.48550/arxiv.2508.16756
