Astronomers have long speculated what happens when a supermassive black hole devours a passing star. Now, a team of European researchers has had the chance to witness it first-hand and actually photograph it for the very first time, Phys.org reports.
Their research, spanning for more than a decade, reveals one particular case of stellar death at the hands of a supermassive black hole 20 million times the mass of the sun, in which the gaping monster feeding on the star released a superfast jet of particles that signaled what was going on.
While these particle jets blasted out by black holes as they munch on stars have been theorized before, this is the first time that one of them was actually caught on camera, so to speak.
After continuously monitoring the event since 2005, the team finally understood what they were dealing with in 2011, when the thing that they had been directly imaging for six years with powerful telescopes began to take the elongated shape of a particle jet.
What’s more, it turned out that this superfast jet ejected by the monster black hole packed 125 billion times more energy than that released by our sun in a whole year, notes Space.com.
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“Never before have we been able to directly observe the formation and evolution of a jet from one of these events,” said Miguel Perez-Torres, an astronomer at the Astrophysical Institute of Andalusia in Granada, Spain, and co-author of a new study detailing this impressive discovery, published yesterday in the journal Science.
Here’s how it all went down.
Some 150 million light-years away from our planet, two colliding galaxies are clenched into a furious battle of life and death. The pair, dubbed Arp 299, had caught the team’s attention because it is known as a “supernova factory,” explains Phys.org. 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.
At the time, the researchers were convinced that their gear — the William Herschel Telescope in the Canary Islands — had picked up a supernova. Half a year later, on July 17, the Very Long Baseline Array (VLBA) of the National Science Foundation detected radio emissions in the same location at the heart of the galaxy.
The source of the infrared and radio emissions, dubbed Arp 299-B AT1, was put under surveillance for more than 10 years with the VLBA, the European VLBI Network (EVN), and other radio telescopes. Six years into the study, Arp 299-B AT1 revealed its true identity as it began to expand in one direction — something that wouldn’t have been observed if this were a supernova.
The data uncovered that the emissions were actually coming from a supermassive black hole inside one of the Arp 299 galaxies, which was found to be 20 million times more massive than the sun.
This enormous black hole had been feasting on a star and was shooting out an incredibly fast particle jet, piercing through the gas and dust disk around it.
Known as a tidal disruption event, this extremely violent occurrence was observed only a few times and has been showed to produce powerful emissions of X-rays and visible, infrared and ultraviolet light in computer simulations, the Inquisitr previously reported.
“The combination of our infrared and radio observations, coupled with state-of-the-art simulations of radio jets and calculations of infrared emission from the dusty regions surrounding a supermassive black hole, left us with one plausible explanation — the infrared and the radio emission came from the disruption of a hapless star being devoured by the supermassive black hole when it passed too close to this cosmic monster,” co-lead author Seppo Mattila, of the University of Turku in Finland, revealed in a statement.
The decade-long observations uncovered that the particles were flying off into space at nearly 25 percent the speed of light, which further confirmed their source as a superfast jet released from a tidal disruption event. By comparison, a supernova only expands at top velocities of about 5 percent the speed of light 10 years after its explosion, Perez-Torres told Space.com.
In addition, the energy emitted during those 10 years by the radio and infrared waves coming off of Arp 299-B AT1 was found to be 125 billion times the amount of energy the sun releases per year.
“As time passed, the new object stayed bright at infrared and radio wavelengths, but not in visible light and X-rays,” said Mattila.
“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,” he explained.
Mattila believes that his team’s discovery will help astronomers spot even more tidal disruption events and understand more about the environment in which galaxies were born.
“Because of the dust that absorbed any visible light, this particular tidal disruption event may be just the tip of the iceberg of what until now has been a hidden population. By looking for these events with infrared and radio telescopes, we may be able to discover many more, and learn from them.”