Astronomers have made an incredible discovery: the largest flare ever seen from a black hole. This flare is also the most distant one observed, coming from a supermassive black hole located 10 billion light-years away in a galaxy known as J2245+3743.
Using the Zwicky Transient Facility (ZTF), scientists found this flare, which is different from typical active galactic nuclei (AGN) events. AGNs contain black holes that feast on nearby gas and dust, forming a structure called an accretion disk. But this particular flare was triggered by a massive star getting too close to the black hole, which is about 500 million times heavier than our Sun. This event, known as a tidal disruption event (TDE), is where the black hole tears the star apart.
Matthew Graham, a team leader at the California Institute of Technology (Caltech), noted that this AGN is unlike anything we’ve encountered before. The flare was first detected in 2018. As researchers monitored it, they found it grew 40 times brighter over several months, peaking at a brightness 30 times greater than any previous flare from black holes. It was emitting energy equivalent to 10 trillion suns. Previously, the most powerful TDE was labeled “Scary Barbie.”
K. E. Saavik Ford, a researcher from the City University of New York, explained that the energy output is astonishing. Using Einstein’s famous equation ( E = mc^2 ), it’s like converting our entire Sun into pure energy.
Interestingly, the flare is fading, suggesting that the black hole is still consuming the unlucky star, which is believed to have started with a mass 30 times that of our Sun. This comparison highlights how massive the star being consumed is compared to others observed in previous TDEs.
Graham likened the continuous nature of the flare to “a fish only halfway down the whale’s gullet.” This ongoing flare allows researchers to study how black holes operate. The gravitational pull around supermassive black holes slows time near them, a phenomenon known as cosmological time dilation. This means that while seven years pass on Earth, only two years seem to go by near the black hole.
The light from this event stretches as it travels through space, giving researchers a unique view of the flare’s evolution at a slower “quarter speed.” Such insights are invaluable for understanding cosmic phenomena.
So far, astronomers have recorded about 100 TDEs, but most occur outside of AGNs. The high activity within AGNs often hides signs of TDEs, making it more challenging to identify them. However, the massive size of J2245+3743 made this particular flare more noticeable.
Initially, this flare didn’t stand out, but in 2023, data from the W. M. Keck Observatory in Hawaii confirmed its extraordinary energy output. Researchers had to rule out other possibilities, like a supernova, before determining it was indeed the brightest black hole flare detected. Ford noted that supernovas lack the brightness necessary to explain this event and suggested that stars within AGN disks can grow unusually large by accumulating matter.
This discovery hints that many similar powerful events might be happening throughout the universe, just waiting to be found. The team will continue scanning the sky with the ZTF and look forward to data from the upcoming Vera C. Rubin Observatory to uncover other significant TDEs.
The findings were published in the journal Nature Astronomy, shedding light on the mysteries of black holes and the cosmos.
