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Galactic Detectives Find Hints of Invisible & Dark Impactor & # 39; Punching Holes in our Galaxy



There is a "dark slogan" blowing hole in our galaxy. We can't see it. It cannot be done in the normal case. Our telescopes have not registered it directly. But it looks like it's out there.

"It's a dense ball of something," said Ana Bonaca, a researcher at the Harvard Smithsonian Center for Astrophysics, who discovered evidence of the impulse.

Bonaca & # 39; s evidence of Dark Impactor, which she presented on April 15 at the American Physical Society conference in Denver, is a series of gaps in our galaxy's longest star, GD-1. Star streams are lines of stars moving together across galaxies, often derived from smaller stars of stars colliding with that galaxy. The stars in GD-1

, remnants of a "spherical cluster" that fell into the winter street a long time ago stretched into a long line above our sky.

Under normal circumstances, the flow must be more or less a single line, stretched out of our galaxy gravity, she said in her presentation. Astronomers would expect a single hole in the stream, at the time the original spherical cluster was before its stars drifted in two directions. But Bonaca showed that GD-1 has another hole. And this hole has a scratched edge – a region Bonaca called GD-1's "spur" – as if something great fell through the stream long ago, and drew stars in the wake of its enormous gravity. GD-1 appears to be hit by the invisible ball. [Gallery: Dark Matter Throughout the Universe]

  This picture from Bonaka's presentation shows the most detailed map yet of GD-1, revealing the apparently different hole and spores.

This picture from Bona's presentation shows the most detailed map yet of GD-1, which reveals the apparent second

Credit: New Astrophysical Probes of Dark Matter, Ana Bonaca / GAIA

"We cannot map [the impactor] for something luminous object that we have observed, "Bonaca told Live Science. "It's a lot more massive than a star … Something like a million times the sun's mass. So there are just no stars of that mass. We can rule it out. And if it was a black hole, it would be a super-massive black Hole of the kind we find in the center of our own galaxy. "

It's not impossible that there is another super-massive black hole in our galaxy," said Bonaca. But we would expect to see some sign of it, like lint or radiation from its accretion disk. And most large galaxies seem to have just one super-massive black hole in their center.

  Top: This image shows what GD-1 looks like. Bottom: This image shows which computer models predict GD-1.

Top: This image shows what GD-1 looks like. Bottom: This image shows which computer models predict GD-1.

Credit: New Astrophysical Probes of Dark Matter, Ana Bonaca / GAIA

Without giant, bright objects that are visible, sliding away from GD-1, and no evidence of a hidden second super-mass black hole in our Galaxy, the only obvious option left, is a large lump of dark matter. That doesn't mean that the object is definitely 100% totally made of dark material, Bonaca said.

"It could be that it is a luminous object that went away somewhere, and it hides somewhere in the galaxy," she added.

But it seems unlikely, partly because of the pure scale of the object.

"We know it's 10 to 20 parsecs [30 to 65 light-years] across," she said. "About the size of a spherical cluster."

  Top: This image shows again what GD-1 looks like. Bottom: This image shows which computer models predict GD-1 would look for an interaction with a large heavy object.

Top: This image shows again what GD-1 looks like. Bottom: This image shows which computer models predict that GD-1 would look for an interaction with a large heavy object.

Credit: New Astrophysical Probes of Dark Matter, Ana Bonaca / GAIA

But it is difficult to completely rule out a luminous object, partly because the researchers do not know how quickly it moved under the effect. (It may have been very quick to move, but not quite as heavily as expected – a true dark ball – Bonaca said. Or it could have been slow to move, but been very massive – a kind of dark hammer.) Without a response to The question, it is impossible to be sure of where the case would be completed.

Still, the possibility of finding a truly dark matter object is tantalizing.

Scientists do not know what dark material is right now. Our universe seems to work as the bright material, the things we can see are only a small part of what is out there. Galaxies bind together as if there is something heavy inside them, whining in their centers and creating enormous gravity. So most physicists justify that there is something else out there, something invisible. There are many different opinions about what it is made of, but none of the efforts to discover the dark matter on the ground have yet worked.

This dense ball of unseen something that throws through our milk path gives physicists a new scrap of evidence the dark matter can be right. And that would indicate that dark material is really "lumpy" as most theories of its behavior predict. [Beyond Higgs: 5 Elusive Particles That May Lurk in the Universe]

If dark matter is "lumpy", it is concentrated in irregular clumps distributed roughly across galaxies – just like the luminous substance we see concentrated in stars and nebulae. Some alternative theories, including theories that suggest dark matter, are not found at all, would not contain any lumps – and would have the effects of dark matter distributed smoothly across galaxies.

So far, Bonaca's discovery is one of a kind, so new that it has not yet been published in a peer-reviewed journal (although it was met by the masses of the crowds at the prestigious conference).

To pull it out, she based herself on data from the Gaia Mission, a European Space Agency Program for mapping billions of stars in our galaxy and their movements across the sky. It formed the best existing catalog of stars that seems to be part of GD-1.

Bonaca pressed these data with observations from the Multi Mirror Telescope in Arizona, which showed which stars moved toward Earth and who moved away. It helped distinguish between stars that really moved with GD-1 and those just sitting next to it in the Earth's sky. This effort produced the most accurate image ever at GD-1, which revealed the second hole, the trace, and a previously invisible region of the star current.

On the way, Bonaca said she would do more mapping projects to reveal other areas of the sky where something unseen seems to be knocking stars around. The goal, she said, is to gradually map out clumps of dark material across the Milky Way.

Originally published on Live Science .


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