Astronomers Discover Largest Explosions Since the Big Bang

The Gaia space telescope has unexpectedly captured a previously unknown type of enormous cosmic explosion—arguably the biggest bursts since the Big Bang itself.

Gigantic Flares from Distant Galaxies

Originating from distant galactic cores, Gaia detected sudden and intense surges in brightness—massive light flares that lasted far longer than any previously documented.

These explosions release energy equivalent to what 100 Suns would emit over their entire lifetimes combined.

Studying the light signatures, scientists found a phenomenon both familiar and new: massive stars being torn apart by supermassive black holes, but on a scale never seen before.

The stars involved were all large—at least three times the mass of our Sun—and each black hole was a supermassive entity at the center of its galaxy.

These events, typically known as tidal disruption events (TDEs), have now been dubbed “extreme nuclear transients” (ENTs) by researchers.

ENTs: Brighter and Longer-Lasting Than Typical TDEs

Astrophysicist Jason Hinkle from the University of Hawaiʻi’s Institute for Astronomy explains, “While we’ve observed stars being destroyed by black holes before, these ENTs are extraordinarily brighter—up to ten times the brightness of typical TDEs—and they remain luminous for years, far outshining even the brightest supernovae.”

Tidal disruption occurs when a star ventures too close to a black hole, and the black hole’s immense gravitational forces overwhelm the star’s own gravity, ripping it apart in a dramatic burst of light before parts fall beyond the event horizon.

Astronomers use wide-field telescopes to catch these fleeting events, watching for sudden bright flares in distant galaxies. TDEs usually show a rapid rise in brightness followed by a slow fade over weeks to months, allowing scientists to analyze the mass and nature of the involved objects.

Although Gaia’s primary mission was to map the Milky Way in 3D by measuring stellar positions, it also captured unusual flares outside its main goals.

Identifying New, Powerful Flare Events

Among these, Hinkle and his team identified two peculiar flares—Gaia16aaw (2016) and Gaia18cdj (2018)—which resembled a powerful event recorded in 2020 by the Zwicky Transient Facility, nicknamed “Scary Barbie” due to its extraordinary brightness.

After thorough analysis, the team ruled out supernovae as the cause, since these flares were at least twice as energetic as any known supernova, whose brightness has an upper limit.

Unlike supernovae, which shine roughly as much as the Sun does over 10 billion years, ENTs emit energy comparable to the combined lifetime output of 100 Suns.

The characteristics of these ENTs closely match scaled-up tidal disruption events, both in energy and the pattern of their brightening and fading.

ENTs are extremely rare—about 10 million times less common than supernovae—but they offer valuable clues about how supermassive black holes grow. These black holes, millions to billions times the Sun’s mass, remain somewhat mysterious in their growth processes, and ENTs may represent one way they gain mass.

Benjamin Shappee, also from the Institute for Astronomy, highlights their significance: “ENTs are brilliant beacons visible across vast cosmic distances, giving us a window into the early universe. Observing these prolonged flares helps us understand black hole growth during cosmic noon, a period when the universe was about half its current age and galaxies were rapidly forming stars and feeding their black holes at rates much higher than today.

Read the original article on: Science Alert

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