For the first time ever, European astronomers recorded a torrent of energy many billions of times more powerful than the annual output of our Sun in a distant galaxy. The source of this monstrous blast was a star getting eaten by a supermassive black hole, an article on Space.com reported.
Thanks to this discovery, the researchers will be able to recognize events like this in the future.
Supermassive black holes like this one are theorized to lie at the center of each and every galaxy. A star that passes too close to this intergalactic Charybdis will end up getting torn apart and devoured in a tidal disruption event.
As the gravity well of a black hole peels apart a star, the stellar matter briefly spins around the black hole before plunging into the event horizon. This brightly shining accretion disk often launches jets of energized particles from its poles that manage to escape into space.
These tidal disruption events are rare. Space is pretty empty, stars are very far apart, and even the biggest supermassive black hole is normally invisible. (Related: The mysterious glow in the Milky Way may be coming from clouds of DIAMONDS in space.)
The few such events that astronomers were lucky enough to find are treasure troves of information. This particular jet was first detected on January 30, 2005 by an observatory in the Canary Islands.
Researchers were studying a pair of colliding galaxies called Arp 299 at the time, hoping to spot a supernova caused by the merging groups. They spotted a sharp burst of infrared light originating in the center of one of those galaxies.
The researchers investigated this mysterious burst using the Very Long Baseline Array (VLBA), a network of widely distributed radio telescopes that could function like a much larger version of themselves. On July 17, 2005, they were able to catch a new burst of radio emissions from the same spot in Arp 299.
“As time passed, the new object stayed bright at infrared and radio wavelengths, but not in visible light and X-rays,” reported Seppo Mattila of the University of Turku, a co-lead author of the study. “The most likely explanation is that thick interstellar gas and dust near the galaxy’s center absorbed the X-rays and visible light, then re-radiated it as infrared.”
They first believed it was a supernova. By 2011, however, the emissions of the event was shown to spread in one direction, while a supernova sent energy in all directions.
The researchers spent almost a decade studying the jet, which they called Arp 299-B AT1. The jet was shown to travel at 25 percent the speed of light. This is five times faster than the expansion speed of a supernova.
Based on their data, the researchers concluded that the jet emission was caused by a tidal disruption event. They estimated the mass of the supermassive black hole in the Arp 299 galaxy to be 20 million times that of our Sun.
The researchers reported that the jet is now breaking up into several parts as it comes across things in its path that affect it. Like most tidal disruption events, Arp 299-B AT1 is difficult to pick up on visible or X-ray wavelengths due to space dust and stellar gas.
Co-lead author Miguel Pérez-Torres of the Astrophysical Institute of Andalusia said studying tidal disruption events offer up clues about the early years of the universe, when they were a much more common occurence.
Learn more about the supermassive black holes at the heart of galaxies – like our own Milky Way – at Cosmic.news.