The largest space explosion in history that suddenly appeared three years ago continues


Astronomers at the University of Southampton have announced the discovery of the most massive cosmic explosion ever recorded, releasing a frightening amount of energy over the past three years.

The explosion, known as AT2021lwx, is more than ten times brighter than any known supernova (exploding star) and three times brighter than the brightest tidal disruption event (when a star falls into a supermassive black hole). It is reportedly 100 times the size of our solar system.

The explosion has been observed for over three years, much longer than most supernovae, and is located nearly 8 billion light years away. Most supernovae last only a few months, but astronomers say this supernova is still being detected by networks of telescopes.

Principal Investigator Dr. Philipp Wiseman said the team made the discovery by accident when a search algorithm flagged it while searching for a type of supernova.

“Most supernovae and tidal disruption events last only a few months before they fade away.

The explosion was first detected by the Twicky Temporary Facility in California in 2020 and subsequently captured by the Asteroid Earth Impact Final Warning System in Hawaii. These facilities survey the night sky to detect transient objects with rapidly changing brightness that indicate cosmic phenomena such as supernovae. It also detects asteroids and comets.

A team of astronomers, whose findings were published in the Royal Astronomical Society’s monthly notice, believe the explosion was caused by a giant gas cloud violently wrecked by a supermassive black hole.

This gas cloud is thought to be thousands of times larger than the Sun.

The disruption caused shock waves to travel through cloud debris and into the large dusty “doughnuts” surrounding the black hole. While this is a rare event in itself, an event of this magnitude has never been witnessed before.

Astronomers separately witnessed the brightest gamma-ray burst on record last year, known as GRB 221009A. It was brighter than the AT2021lwx, but lasted only a fraction of the time. This means that the total energy released by AT2021lwx’s explosion is much higher.

Distance analysis and measurement

A team of astronomers investigated the cosmic explosion using several separate telescopes. It also includes the Neil Gerels Swift Telescope, a joint development of NASA, the UK and Italy. The new technology telescope is operated by the European Southern Observatory in Chile. Gran Telescopio Canarias in La Palma, Spain.

By analyzing the spectrum of light, the team was able to measure the distance to the object and calculate the brightness of the object at the light source. They found the explosion to be as bright as a quasar. A quasar is a supermassive black hole with a constant stream of gas raining down at high speed.

However, the researchers noted that while the brightness of quasars typically changes over time, the explosion was sudden and incomparable in brightness. Professor Mark Sullivan, also from the University of Southampton and another co-author of the paper, explains.

“In a quasar, you would see the brightness flashing up and down over time,” he said. “But looking back over a decade, AT2021lwx was never detected, but suddenly appeared with a brightness like the brightest thing in the universe. This is unprecedented.”

The researchers believe the most plausible explanation for the explosion is that a very large cloud of gas or dust flew out of orbit around the black hole.

They plan to collect more data about the explosion, including measurements of different wavelengths, to reveal the surface and temperature of the object, and learn more about the underlying processes taking place.

By analyzing the spectrum of light, splitting the wavelengths, and measuring various absorption and emission characteristics, the research team was able to determine the distance to the object.

“If we know the distance to an object and how bright it appears to us, we can calculate the brightness at the source of the object. When we performed these calculations, we found that this was very bright. said co-author of the study, Professor Sebastian Hennig of the University of Southampton.

Astronomers hope to discover more such phenomena using new facilities such as the Vera Rubin Observatory’s Legacy Survey of Space and Time, which will be operational in the next few years. .

“These events, though very rare, are so energetic that they could be important processes in how the galactic center changes over time,” Weisman said. added.