Astronomers discover strange new black-hole stars

“The discovery was pure serendipity,” says Karl Glazebrook, distinguished professor of astronomy at Swinburne. Today, many new astronomical discoveries are made through computer analysis of images. These are not. “I get them looking at the pictures and saying, ‘What the hell is this?’ We discovered it by saying “

Almost all of the points are very old; It is only hundreds of millions of years younger than the Big Bang. Could these be small, old galaxies? Them He looked too strong for that.Although it is a very small part of the Milky Way, it emits a large amount of energy. It’s hard to understand how they form so many stars so quickly.

To understand what they’re looking at, astronomers divide the light from a source into a rainbow spectrum and look for any peaks or troughs; Certain molecules are known to emit or block certain colors of light.

The small red dots were emitting infrared light and ultraviolet light; It emitted almost nothing else. Further evidence from the spectra revealed the existence of various gases moving at very high speeds.

“The signature of energy distribution was unlike anything we’d seen before,” says Glazebrook.

This led to an early theory: a supermassive black hole eating a cloud of gas. As the hole absorbs gas, it can spin at extreme speed and emit light. But these objects typically emit X-ray bursts, and the tiny red dots do not.

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No bright light, no gas moving at extreme speeds, no X-ray bursts; the picture was difficult to explain with known objects. Earlier this year, astronomers proposed a new one: a black hole star. “It looks like a giant star with a black hole at its center and a temperature of 10,000 Kelvin,” says Glazebrook. “This is emerging as the favorite theory.”

“It acts like a thick atmosphere of gas surrounding the black hole, like the surface of a star.”

Massive black holes are often found at the center of galaxies (there is one at the heart of the Milky Way, happily swallowing stars). A black hole star replaces all stars with a huge cloud of gas; It moves so fast that it has no chance of turning into stars. A galaxy stopped. gas is known Effectively absorbs X-ray light.

It is not clear how a gas cloud can remain stably suspended around a black hole. Perhaps the heat produced by the black hole could support the gas cloud, hiding much of the emissions normally coming from the black hole. The gas cloud itself can shine from the heat of the black hole, just like a star itself.

“How can they be stable? I don’t know,” says Glazebrook. “We don’t know how they form.”

One idea: the decades-old “starlike” theory, which proposes that the early universe was full of supergiant stars much larger than the ones we see today. They eventually collapsed into a black hole surrounded by a huge cloud of gas. The presence of small red dots seems to revive this idea.

But for now, all of this remains speculation.

“We still don’t understand what these are,” says Davies. “We still don’t fully understand what we’re looking at.”

He says their existence tells us two things: Strange things were happening in the early universe, and we still have a lot to learn.

“These little red dots show that there were many more growing black holes in the early universe than we have previously discovered.”

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