Supermassive black hole is spinning slower than expected and we don’t know why

(ORDO NEWS) — Black holes. They used to be theoretical until the first one was found and confirmed back in the late 20th century. Now astronomers find them everywhere. We even have direct radio images of two black holes: one in M87 and Sagittarius A* at the center of our galaxy.

So what do we know about them? A lot of. But there is more to find out.

A team of astronomers using data from the Chandra X-ray Observatory have made a startling discovery about a supermassive black hole at the center of a quasar embedded in a distant cluster of galaxies. What they found provides clues to the origin and evolution of supermassive black holes.

Two-factor identification of black holes

If you are going to study a black hole, especially a supermassive one, you will have to face a lot of problems.

t turns out that every large galaxy has a monster central black hole. Therefore, it is important to know as much as possible about them. These space giants have a mass of millions or even billions of solar masses.

They have a strong gravitational pull and nothing, not even light, can escape from their clutches. This affects our ability to look at them and nearby regions.

One point is not quite clear yet: how do these monsters form and evolve?

The answer lies in part in two of their characteristics. “Each black hole can be defined by just two numbers: its spin and its mass,” said Julia Sisk-Raines of the University of Cambridge’s Institute of Astronomy (IoA) in the UK, who led the new supermassive black hole study. the hole is about 3.6 billion years away.

“Although it sounds pretty simple, calculating these values ​​for most black holes has proven to be incredibly difficult.”

X-ray emission from a black hole

Measuring masses is difficult, although there are ways to do it. Measuring rotation is a real challenge. To learn more about monstrous black holes, Sisk-Reins and his colleagues used data from the Chandra X-ray Observatory.

They studied observations of the H1821+643 quasar’s central supermassive black hole and may have obtained its spin rate. . It contains 30 billion times the mass of the Sun. (For comparison, the Milky Way’s central supermassive black hole has a mass of only about 4 million solar masses.)

Why x-rays? A spinning black hole drags space along with it and allows matter to spin closer to itself than is possible for a non-spinning hole. X-ray data show how fast a black hole is spinning.

Studies of the spectrum of H1821+643 show that its black hole’s spin rate is strange compared to other, less massive ones that spin at close to light speeds. This lower speed of the quasar black hole surprised the team.

“We found that the black hole in H1821+643 rotates about half as fast as most black holes weighing between a million and ten million suns. – said astronomer Christopher Reynolds (also from the Institute of Astronomy). He is the co-author of a paper reporting Chandra measurements. “The Million Dollar Question: Why?”

Black holes: origin and evolution

History of H1821 According to co-author James Matthews (also of the Institute of Astronomy), +643 may provide clues to the slower rotation speed.

He suggests that supermassive black holes like H1821+643 most likely grew by merging with other black holes during galaxy collisions.

It is well known that collisions of galaxies lead to the formation of larger galaxies over time, so the same actions (including collisions of dwarf galaxies) are as fair as possible. factors.

It is also possible that the outer disk of this black hole collapsed as a result of a collision, due to which gas was blown in random directions during the event.

These kinds of actions can affect the spin rates of a black hole—slowing it down or even spinning it in a completely new direction. This means that such black holes can exhibit different spin rates depending on their recent history.

“The moderate rotation of this supermassive object may be evidence of the turbulent and chaotic history of the largest black holes in the universe. ‘ Matthews said.

“It could also provide insight into what will happen to our galaxy’s supermassive black hole billions of years into the future when the Milky Way collides with Andromeda and other galaxies.”

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