Black Hole Reawakens Like a Cosmic Volcano After 100 Million Years of Sleep
After lying dormant for nearly 100 million years, a supermassive black hole came back to life – and astronomers caught it in the act. New radio images, published in Monthly Notices of the Royal Astronomical Societyreveal the black hole at the heart of galaxy J1007+3540 restarting its jets, producing one of the clearest examples yet of a so-called “reborn” black hole.
The scene, compared by researchers to a volcanic eruption of almost unimaginable scale, spans nearly a million light years. Captured using two of the world’s most sensitive radio observatories, the images offer insight into how black holes can shut down, reignite and reshape entire galaxies.
“It’s like watching a cosmic volcano erupt again after periods of calm, except this one is large enough to carve structures spanning nearly a million light years across space,” lead researcher Shobha Kumari said in a press release.
How do black holes turn on and off again?
Most large galaxies host supermassive black holes at their centers, but only a small fraction actively launches enormous jets of magnetized plasma that glow at radio wavelengths. J1007+3540 stands out because it shows evidence of multiple jet explosions, revealing that its central black hole has alternated between active and quiet phases.
The galaxy’s black hole recently restarted its jet emission after a long period of silence, creating a compact, bright inner jet – a telltale sign of a newly awakened engine. Older, discolored plasma surrounds the black hole, which is likely made up of debris left behind by previous eruptions millions of years earlier.
“This spectacular superposition of young jets inside older, exhausted lobes is the signature of an episodic AGN – a galaxy whose central engine keeps turning on and off over cosmic timescales,” Kumari explained.
Learn more: Supermassive black hole flare launched wind and debris into space at 37,000 miles per second
What did the radio images reveal about J1007+3540
The images were obtained using the Low Frequency Array (LOFAR) in the Netherlands and India’s Metrewave Enhanced Giant Radio Telescope (uGMRT). Together, they revealed different aspects of this exciting cosmic event.
J1007+3540 resides inside a massive galaxy cluster filled with extremely hot gas, creating intense external pressure. As the awakened jets push outward, they become distorted. This distortion was captured in LOFAR images, which showed the curved and twisted shape of J1007+3540’s northern lobe.
The uGMRT data showed that the northern lobe includes particles that are extremely old and have lost much of their energy. Additionally, the images showed that magnetized plasma is being pulled through the cluster toward the southwest, leaving a long tail likely millions of years old.
What have astronomers learned from these images?
Systems like J1007+3540 are particularly valuable because they capture the evolution of galaxies in action. They reveal how black holes pass through active phases, how jets age and fade, and how dense cluster environments can sculpt the entire structure of a galaxy. Rather than growing smoothly, research suggests that galaxies evolve through violent clashes.
The team now plans to conduct even more sensitive, high-resolution observations to delve deeper into the galaxy’s core and track how the restarted jets continue to spread through their surroundings.
Learn more: The closest black hole to Earth is Gaia BH1, just 1,600 light years away
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