HEAPOW: What's Happening Behind a Black Hole? (2021 Aug 02)

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bystander
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HEAPOW: What's Happening Behind a Black Hole? (2021 Aug 02)

Post by bystander » Mon Aug 02, 2021 4:03 pm

Image HEAPOW: What's Happening Behind a Black Hole? (2021 Aug 02)

Although nothing, not even light or other forms of electromagnetic radiation, can escape from inside a black hole, black holes still have ways of making their presence known to us. When matter falls into a black hole, it heats up and radiates, providing us a way to "see" the black hole via the radiation emitted by this material before it passes within the black hole's event horizon. Material that the black hole accretes doesn't fall directly into the black hole, however; rather it forms a hot, thin, spinning disk around the black hole, before spiraling through the event horizon, never to be seen again. Because the inner parts of these spiraling accretion disks are so hot and energetic, they produce enormous amounts of X-rays. Detailed studies of the X-rays from the inner parts of accretion disks provide our best way to test the effects of the strong gravity of the black hole on nearby space, all from a safe distance. A recent study of the X-rays emitted near the supermassive black hole at the heart of a galaxy called I Zwicky 1 by the NuSTAR and XMM-Newton X-ray space observatories has provided us with an extraordinarily detailed look at the spacetime just beyond the edge of a black hole. The illustration above shows the accretion disk (colored red) surrounding the black hole, warped by the black hole's gravity, along with a jet of material escaping from the black hole, and an extended region of hot gas, or corona, close to the black hole. The accretion process can be unstable and variable. By studying the time-delayed echoes of X-ray flashes from the jet and corona that are reflected off the accretion disk, scientists can derive a detailed mapping of the motion of the disk of material, and even the spin of the black hole, and produce a picture of the distortions of spacetime near the edge of the black hole. And, for the first time ever, these scientists have shown evidence that some of the variable emission arises from material that's actually behind the black hole, warped and bent into our view and magnified by black hole's strong gravitational field. These new observations confirm a key prediction of Einstein's theory of general relativity, that gravitational fields can bend X-rays (and other forms of electromagnetic radiation) which can allow us to "see" behind a black hole.



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bystander
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First Detection of Light Echoes from Behind a Black Hole

Post by bystander » Mon Aug 02, 2021 4:31 pm

First Detection of Light from Behind a Black Hole
Netherlands Institute for Space Research (SRON) | 2021 Jul 29

First Detection of Light from Behind a Black Hole
Stanford University | KIPAC | SLAC | 2021 Jul 28

First Detection of Light Echoes from Behind a Black Hole
Eberly College of Science | Penn State University | 2021 Jul 28
disc_reverb_v2.jpg
Illustration of a bright flare of X-ray emission and its echoes produced as gas falls
into a supermassive black hole and reflects off of the gas falling into the black hole.
Researchers have reported the first recording of these X-ray echoes consistent
with X-rays reflected from behind the black hole. Credit: Dan Wilkins

Researchers report the first-ever recordings of X-ray emission from the far side of a black hole. The discovery ... is the first direct observation of light from behind a black hole—a scenario that was predicted by Einstein’s theory of general relativity but never confirmed, until now.

Watching X-rays flung out into the universe by the supermassive black hole at the center of a galaxy 800 million light-years away, the researchers noticed an intriguing pattern. They observed a series of bright flares of X-rays—exciting, but not unprecedented—and then, the telescopes recorded something unexpected: additional flashes of X-rays that were smaller, later, and of different “colors” than the bright flares. ...

According to theory, the luminous echoes observed were consistent with X-rays reflected from behind the black hole—but even a basic understanding of black holes tells us that is a strange place for light to come from. ...

XMM-Newton Sees Light Echo from Behind a Black Hole
ESA | Science & Technology | XMM-Newton | 2021 Jul 28

Light Bending and X-ray Echoes from Behind a Supermassive Black Hole ~ D. R. Wilkins et al
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Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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saturno2
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Re: HEAPOW: What's Happening Behind a Black Hole? (2021 Aug 02)

Post by saturno2 » Tue Aug 24, 2021 12:04 am

Very interesting