Published: Sun, June 17, 2018
Sci-tech | By April Francis

Black Hole Swallows Star, Belches Particles as Scientists Watch

Black Hole Swallows Star, Belches Particles as Scientists Watch

According to theoretical models, in tidal disruption events, in which a black hole tears a star, half of the star's mass is expelled into space, while the other half is absorbed by the supermassive black hole. This is known as a tidal disruption event and, although it is hypothesised to be a regular occurrence throughout the galaxy, little is known about what happens during these stellar deaths.

When the black hole devoured the star, it shot out a fast group of particles that contained 125 billion times the amount of energy that the sun releases annually. Since the researchers were hunting for supernovas in galactic mergers, they pointed their telescopes at Arp 299 and, sure enough, on January 30, 2005, they detected a source of bright infrared light nestled within one of the two galaxies.

An image of the galaxy Arp299B, which is undergoing a merging process with Arp299A (the galaxy to the left), captured by NASA's Hubble space telescope.

Astronomers witnessed a huge black hole rip apart a star that just happened to move a little closer to it. A TDE was recently observed near the center of Arp299B.

"As time passed, the new object stayed bright at infrared and radio wavelengths, but not in visible light and X-rays", said Dr Seppo Mattila, of the University of Turku in Finland. These multiple radio antennas separated by thousands of kilometers allow the VLBA to gain an incredible resolving power - the ability to see fine detail - which is required to observe the features of an expanding object from millions of light-years away. Part of the matter of the star is expelled to the poles of the black hole via magnetic field lines and ejected in the form of a stream of relativistic particles. The material of the star falls into the black hole. This is the phenomenon seen in radio galaxies and quasars.

"TDEs can provide us with a unique opportunity to advance our understanding of the formation and evolution of jets in the vicinities of these powerful objects", Dr. Perez-Torres said. Whatever it was, it didn't emit significant visible light, probably because the surrounding dust absorbed the visible light and re-radiated it as infrared. In order to be able to watch this impressive event, they used highly-advanced telescopes.

Dr Rob Beswick, from the Jodrell Bank Centre for Astrophysics at the University of Manchester's School of Physics and Astronomy, UK, said: "This is a fantastic discovery and an extremely important result in astronomy". Researchers were able to record an explosion of infrared emission from the nucleus in a galaxy located in Arp 299.

And the astronomers were also intrigued by radio waves - formed by debris from the trapped star - travelling at almost light-speed from Arp 299.

Originally those jets, from Earth, appeared as a supernova.

As the work continued from various telescopes, the group witnessed the distant radio emission's expansion.

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