The universe’s brightest supernova ever may be something far more rare. An extraordinary display of light in a distant galaxy that had been previously dubbed brightest supernova ever turned out to be a giant black hole tearing apart a massive star.
The luminous event, named ASASSN-15lh, took place in 2015, inside a galaxy 4 billion light years away from the Earth. It was detected using All Sky Automated Survey and was thought to be the brightest and most powerful supernova on record. Supernova is a massive explosion that takes place at the ending stages of a star’s life cycle, resulting in the destruction of the star.
Supernovae are the largest explosions observed in the space and the latest outburst was so bright that at one point it outshined all the stars in the Milky Way combined. So, it could be easily mistaken for a supernova explosion.
When a team of international researchers made additional observations of the galaxy where the explosion took place, they found it was something much more exciting than a supernova and proposed a new explanation for this extraordinary event. The outburst was the result of a supermassive black hole ripping apart a massive star that came too close and eventually being swallowed by the black hole.
“We observed the source for 10 months following the event and have concluded that the explanation is unlikely to lie with an extraordinarily bright supernova. Our results indicate that the event was probably caused by a rapidly spinning supermassive black hole as it destroyed a low-mass star.” Principal investigator Giorgos Leloudas from Weizmann Institute of Science in Israel explained.
After 10 months of follow up observations, researchers have found that the event was more closely resemble a tidal disruption rather than a supernova. The extreme gravitational field exerted by the black hole pulled apart the wandering star and caused an intense burst of light. This gave the impression of an extremely bright supernova explosion, even though the star did not have enough mass to become a supernova on its own. Furthermore, the event occurred in a red, massive galaxy which is an unusual location for a supernova explosion. Superlumious supernova usually takes place in blue, dwarf galaxies that are filled with star forming material.
Hira Bashir covers daily affairs around the world.