In a distant galaxy, a supermassive black hole has unleashed a torrent of light so powerful it outshines 10 trillion suns, an event more luminous and longer-lasting than any previously recorded. The flare, which traveled for 10 billion years to reach Earth, provides an unprecedented view into the violent dynamics of the early universe and the feeding habits of the cosmic behemoths that lurk at the centers of galaxies.
First detected in 2018, the colossal eruption of energy comes from a black hole tearing apart a massive star that wandered too close. Researchers analyzing the event, catalogued as J2245+3743, have now confirmed its extreme nature in a study published in the journal Nature Astronomy. The flare brightened by a factor of 40 over several months and peaked at a luminosity 30 times greater than any other black hole flare observed to date, offering astronomers a rare, extended look at a phenomenon known as a tidal disruption event (TDE). Its immense distance means scientists are effectively looking back in time, observing a cataclysm that unfolded when the universe was still in its relative youth.
Anatomy of a Colossal Flare
The event, J2245+3743, stands out for its sheer scale and persistence. At its peak, the flare’s energy output was staggering, releasing the equivalent of transforming our sun’s entire mass into pure radiation. After reaching this maximum brightness over a period of about three months in 2018, the flare has been slowly fading for more than seven years. This long duration provides a wealth of data for astrophysicists studying the physics of black hole accretion disks, the swirling masses of gas and debris that form around a black hole as it feeds.
The black hole responsible is estimated to be 500 million times the mass of the sun. The leading explanation for the flare is that a star at least 30 times more massive than our sun was captured and shredded by the black hole’s immense gravitational forces. As the star’s material was pulled apart, it heated up to extreme temperatures and was flung into the accretion disk, causing the dramatic and sustained surge in brightness. According to Matthew Graham, a research professor at the California Institute of Technology who led the study, the object’s brightness combined with its distance made it immediately clear that it was “something unusual and very interesting.”
Observation and Discovery
A Serendipitous Finding
The flare was first captured in 2018 by automated sky surveys at Caltech’s Palomar Observatory. The Zwicky Transient Facility (ZTF) and the Catalina Real-Time Transient Survey, both designed to detect transient celestial events like supernovae and asteroids, registered a new, intensely bright point of light. However, its extraordinary nature was not immediately recognized. It was only during a retrospective analysis of archival data in 2023 that researchers calculated the object’s vast distance and, consequently, its astonishing intrinsic luminosity. “At first, we didn’t really believe the numbers about the energy,” Graham stated, highlighting the initial shock at the scale of the event.
Ruling Out Alternatives
To confirm the flare’s nature, the team had to consider other possibilities. Some supermassive black holes emit powerful, narrowly focused jets of energy, which can appear deceptively bright if pointed directly at Earth. However, multi-wavelength data, including observations from NASA’s Wide-field Infrared Survey Explorer (WISE) mission, indicated that the light was being radiated isotropically, or in all directions, rather than in a tightly collimated beam. This finding supported the tidal disruption event hypothesis over other explanations, such as a different type of active galactic nucleus (AGN) behavior.
A Glimpse into the Early Universe
Observing an event from 10 billion light-years away offers a window into conditions in the cosmos when it was less than 4 billion years old. Studying phenomena from this era helps scientists understand how the first supermassive black holes formed and grew to such enormous sizes so quickly, a major puzzle in modern cosmology. The immense energy of J2245+3743 provides clues about the density and composition of the environment surrounding major black holes in this early epoch.
Furthermore, due to the expansion of the universe, the light from J2245+3743 is subject to cosmological time dilation. This effect stretches not only the wavelength of the light but also the timescale of the event itself from our perspective. Graham explained that the seven years of observation on Earth correspond to roughly two years in the flare’s own reference frame. This cosmic “slow motion” playback allows for a more detailed examination of the TDE’s evolution, including the physics of how the stellar material accretes onto the black hole and dissipates energy over time.
An Unusual Tidal Disruption Event
What makes this event particularly significant is that it occurred in an active galactic nucleus, a region where the supermassive black hole is already actively feeding on a steady supply of gas and dust. Most tidal disruption events previously observed have been in relatively quiet galactic centers. In this case, the flare from the shredded star was so intense that it completely dwarfed the normal, already-luminous output of the black hole’s existing accretion disk.
This discovery suggests that TDEs may be more common in AGNs than previously thought, but perhaps often missed against the bright background of the active nucleus. Identifying such an extreme outlier as J2245+3743 helps astronomers refine their models of black hole growth and interaction with their host galaxies. The ongoing, gradual fading of the flare will continue to be monitored by ground-based telescopes, providing a rare, long-term case study of the aftermath of stellar destruction on a cosmic scale.
