Astronomers Uncover Most Powerful Explosion Since The Big Bang

Astronomers from the University of Hawai'i's Institute for Astronomy have identified a new class of cosmic explosions, termed "extreme nuclear transients" (ENTs), marking the most energetic events observed since the Big Bang. These phenomena occur when massive stars, at least three times the mass of our Sun, are torn apart by supermassive black holes at the centres of distant galaxies. The resulting explosions release energy equivalent to what 100 Suns would emit over their entire lifespans, making them visible across vast cosmic distances. This discovery offers new insights into the dynamic interactions between stars and black holes in the universe.

The team's findings were detailed today in the journal Science Advances.

"We've observed stars getting ripped apart as tidal disruption events for over a decade, but these ENTs are different beasts, reaching brightnesses nearly ten times more than what we typically see," said Jason Hinkle, in a statement, who led the study as the final piece of his doctoral research at IfA. "Not only are ENTs far brighter than normal tidal disruption events, but they remain luminous for years, far surpassing the energy output of even the brightest known supernova explosions."

The immense luminosities and energies of these ENTs are truly unprecedented. The most energetic ENT studied, named Gaia18cdj, emitted an astonishing 25 times more energy than the most energetic supernovae known. While typical supernovae emit as much energy in just one year as the sun does in its 10 billion-year lifetime, ENTs radiate the energy of 100 suns over a single year.

As per a news release by W M Keck Observatory, ENTs were first uncovered when Hinkle began a systematic search of public transient surveys for long-lived flares emanating from the centres of galaxies. He identified two unusual flares in data from the European Space Agency's Gaia mission that brightened over a timescale much longer than known transients and without characteristics common to known transients.

"Gaia doesn't tell you what a transient is, just that something changed in brightness," said Hinkle. "But when I saw these smooth, long-lived flares from the centres of distant galaxies, I knew we were looking at something unusual."