This supermassive black hole spins slower than expected, and we’re not sure why

Black Holes. They used to be theoretical, until first found and confirmed back in the late 20th century. Now, astronomers find them everywhere. We also 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? very. But, there is much more to find out.

A team of astronomers using Chandra X-ray Observatory data has made a startling discovery about a central supermassive black hole in a quasar embedded in a distant galaxy cluster. What they found provided clues to the origin and evolution of supermassive black holes.

Two-factor identification of black holes

If you’re going to study a black hole, especially a supermassive one, there are a lot of challenges. It turns out that every major galaxy has a central monster black hole. Therefore, it is important that we get to know as much as possible about them. These cosmic behemoths contain millions or even billions of solar masses.

They have strong gravitational pull – and nothing, not even light, can escape from their clutches. This affects our ability to see them and the areas around them.

One thing that’s not clear yet: How do these monsters form and evolve?

The answer partly lies in their two characteristics. “Every black hole can be defined by just two numbers: its spin and its mass,” said Julia Sisk-Raines of the Institute for Astronomy (IOA) at the University of Cambridge in the UK. hole 3.6 billion years away from us.

“While this sounds simple enough, detecting those values ​​for most black holes has proven incredibly difficult.”

X-raying a black hole

Mass is difficult to measure, although there are ways to do it. Measuring spin is a real challenge. To learn more about the monster black hole, Sisk-Raines and colleagues used data from the Chandra X-ray Observatory.

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

Why X-rays? A rotating black hole drags the space around it and allows matter to orbit close to it, which is not possible for a non-spinning one. X-ray data shows how fast a black hole spins.

Studies of the spectrum of H1821+643 show that its black hole rotation rate is peculiar compared to other less massive ones that rotate at close to the speed of light. The slow motion of the quasar’s black hole surprised the team.

Astronomer Christopher Reynolds (also of the Institute of Astronomy) said, “We found that the black hole in H1821+643 is rotating about half as fast as most black holes weighing between about a million and a million suns.” He is a co-author of the paper reporting the results of the lunar measurements. “The million-dollar question is: why?”

Black Holes: Origin and Evolution

According to co-author James Matthews (also at the Institute of Astronomy), the history of H1821+643 may hold the key to understanding its slow spin rate.

They suggest that supermassive black holes like H1821+643 are likely to grow through mergers with other black holes during the collisions of their galaxies.

It is well known that galaxy collisions create larger galaxies over time, and so the same activities (including collisions of dwarf galaxies) are fair game as potential factors.

It is also possible that this black hole’s outer disk may have been disrupted in a collision that sent gas out in random directions during the event.

These kinds of activities affect the black hole’s spin rate – slowing it down, or even causing it to spin in an entirely new direction. This means that such black holes can show a variety of spin rates depending on their recent history.

“The moderate spin for this ultramassive object may be a testament to the violent, chaotic history of the universe’s largest black hole,” Mathews said.

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

This article was originally published by Universe Today. Read the original article.


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