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Some black holes are so old that we can not explain them. This could be where they came from



Supermassive black holes (SMBH) are difficult to explain. It is believed that these gigantic singularities are at the center of every great galaxy (our Milky Way has one), but their presence there is sometimes inexplicable.

As far as we know, black holes form when huge stars collapse. However, this explanation does not fit with all the evidence.

The star collapse hypothesis provides a good explanation for most black holes. In this hypothesis, a star that is at least five times as massive as our sun will run out of fuel towards the end of its life. Since the external pressure of the nuclear fusion of a star supports it against the internal gravity of its own mass, something must yield when the fuel runs out.

The star goes through a hypernova explosion and then collapses. What remains is a black hole. Astrophysicists believe that SMBHs begin on this path and grow to their enormous size by essentially "feeding" on other things. They swell in size and sit in the center of their gravity like a spider that contracts in the middle of its web.

The problem with this explanation is that it takes a long time for it to happen.   (ESO / L. Calçada / CC BY 4.0)

(ESO / L. Calçada / CC BY 4.0)

BILD: This artist's depiction shows the surroundings of a supermassive black hole that is typical of the heart of many galaxies. The black hole itself is surrounded by a brilliant accretion disk of very hot, accumulating material and farther outward by a dusty torus. There are also often high-speed material jets that are ejected at the poles of the black hole and can extend over long distances into space.

Out there in the universe, scientists have observed SMBHs that are ancient. In March of this year, a group of astronomers announced the discovery of 83 SMBHs that are so old they resisted our understanding.

In 2017, astronomers discovered an 800 million solar mass black hole, which was formed only 690 million years after the Big Bang. They originated in the early days of the universe, before there was time to develop into their over-abundant forms.

Many of these SMBHs are billion times more massive than the Sun. They are in such high redshifts that they must have arisen in the first 800 million years after the Big Bang.

But the star collapse model does not have enough time to explain it. The question astrophysicists ask is how these black holes have grown so large in such a short time.

A team of researchers at Western University in Ontario, Canada, thinks they have found out. They have a new hypothesis called "direct collapse" that explains these incredibly old SMBHs.

Her work is titled "The Mass Function of Supermassive Black Holes in the Scenario of Direct Collapse" and is published in The Astrophysical Journal Letters .

The authors are Shantanu Basu and Arpan Das. Basu is a recognized expert in the early stages of star formation and the evolution of protoplanetary disks. He is also a professor of astronomy at Western University. This also comes from the Western Department of Physics and Astronomy.

Their direct collapse hypothesis states that the ancient supermassive black holes have formed extremely rapidly in very short periods of time. Then they suddenly stopped growing.

They developed a new mathematical model to explain these fast-forming, ancient black holes. It is said that the Eddington boundary, which represents a balance between the outward radiant power of a star and the inward gravitational force, plays a role.

In these directly collapsing black holes, the Eddington frontier regulates mass growth that these ancient black holes may even slightly exceed this limit, what they call a super Eddington accretion. Due to the radiation generated by other stars and black holes, their production was discontinued.

"Supermassive black holes only lasted a short amount of time, allowing them to grow quickly and eventually, due to all the radiation in the" The universe created by other black holes and stars has stopped production, "explains Basu in a press release, "This is the direct collapse scenario."

"This is indirect evidence that black holes are from direct collapse rather than star remnants," Basu said.

This new hypothesis provides one An Effective Explanation of What has been a sensitive issue in astronomy for some time now, Basu believes that these new findings can be used with future observations to trace the genesis of the extremely massive black holes that exist in our universe at very early times .

This article was originally published by Universe Today The original article.


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