November 28, 2022

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Black hole spewing stellar debris |  urania

Black hole spewing stellar debris | urania

For the first time, astronomers see a black hole spewing out stellar debris years after it swallowed a star.

In October 2018, a young star was torn to shreds when he passed close to him Black hole in galaxy Located in 665 million light years from Earth. While this event may seem captivating, it comes as no surprise to astronomers who occasionally witness such violent incidents while scanning the night sky.

But three years after that, the same black hole lit up in the sky again — and swallowed nothing new, scientists say.

This surprised us – no one’s seen anything like it before – says Yvette Sindis, a researcher at the Center for Astrophysics | Harvard and Smithsonian (CfA) and lead author of the new the exams phenomenon analysis.

The team concluded that the black hole is now ejecting matter moving at half the speed of light. https://pl.wikipedia.org/wiki/Prędowość_wiatła But they are not sure why the outflow was delayed for several years. The findings, published in The Astrophysical Journal, could help scientists better understand the behavior of black holes during absorptions, which Sendys likens to “hiccups” after a meal.

The team noticed an unusual explosion while reviewing the events Tidal disturbance events (TDE) – When it gets close to stars it is torn apart by black holes – which has happened in the past few years.

Radio data from very large array (VLA) It showed that the black hole mysteriously resurrected in June 2021. Cendes and the team decided to further investigate the event.

The team collected observations of a TDE event, called AT2018hyz, at multiple wavelengths of light using the VLA Observatory. Alma In Chile, MeerKAT in South Africa, Australian Compact Telescope Group In Australia and space observatories blues And the Swift.

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The TDE radio observations turned out to be the most striking.

We’ve studied the phenomenon of TDE using radio telescopes for more than a decade, and sometimes find that it glows in radio waves as matter ejects when a black hole first swallows the star. says Ido Berger, Harvard professor of astronomy and CfA and co-author of the new study. But the AT2018hyz was in radio silence for the first three years, and now it’s lit up dramatically, becoming one of the most glowing radio TDEs ever.

Sebastian Gomez, co-author of the article who worked on his doctoral thesis with Berger, used theoretical models to calculate that the star torn apart by the black hole was only 1/10 the mass of our sun.

TDEs are notorious for emitting light when they appear. As the star approaches the black hole, gravitational forces begin to stretch the star. Eventually, the expanding matter orbits around the black hole and heats up, creating a flash that astronomers can see from millions of light years away.

Sometimes some shredded material is thrown into space. Astronomers compare this to black holes, which are messy eaters – and not everything they try to devour ends up inside them.

However, the emission, known as flux, usually develops rapidly after a TDE occurs — not years later. “It’s as if a black hole suddenly started ejecting a lump of material from a star that swept it up years ago,” Seendez explains.

The flow of matter travels to 50% of the speed of light. By comparison, most TDEs have an outflow that travels at 10% the speed of light, Cendes says.

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This is the first time we have seen such a long delay between feeding and leaving Berger says. The next step is to check if this really happens too often, and we haven’t looked at TDE events late enough in their development.

Detail:
Agnieszka Nowak

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Source: Harvard University

Pictured: An artistic view of a tidal rupture as a supermassive black hole ruptures and devours a star. Some of this material has not been consumed and is being returned to space. Source: DESY, Scientific Communication Laboratory.