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amdudus, Fri May 17, 2019 5:01 pm

Astronomers: Something unknown like a bullet punched a hole inside the Milky Way
Scientists at the Harvard-Smithsonian Center for Astrophysics at a loss. Something “unknown, dense, invisible through telescopes and consisting, most likely, not of ordinary matter, as if a bullet pierced and made giant holes inside our Milky Way galaxy”. Evidence of this was presented at the conference of the American Physical Society in Denver (USA) by astrophysicist Anna Bonaka.
The holes it has discovered in the Milky Way are located in the longest stellar flow GD-1. They are groups of stars moving along the orbits of galaxies. Once they were a small globular cluster or dwarf galaxy, and now fly away.
Under normal conditions, the researcher notes, the flow should be drawn more or less into a line with one break where the globular cluster was originally located before the stars began to fly in different directions. But Bonaca demonstrated that GD-1 has a second gap. Interestingly, this second gap has torn edges - as if something huge broke through the stream not so long ago and dragged behind it some of the stars under the influence of the enormous force of gravity.
“We cannot attribute this phenomenon to any luminous object that we have observed before. It is something much more massive than a star. Something a million times more massive than our Sun. There are no stars of such a mass. We cannot explain it. If it were a black hole, it would have to be as supermassive as the one in the center of our galaxy, ”Bonaka told Live Science in an interview.
The scientist believes that, of course, it is impossible to rule out the possibility of a second supermassive black hole in the Milky Way. However, in this case, we would have noticed some signs of its presence, for example, a flash or the emission of its accretion disk. At the same time, an astrophysicist notes, most large galaxies have only one supermassive black hole in the center.
Another hypothesis of a scientist is a large clot of dark matter. However, Bonaka notes that the object is not necessarily completely, 100% of dark matter.
“Perhaps this is a luminous object that is hiding somewhere in the galaxy. However, this is unlikely, since its size - and it’s about 10–20 parsecs (30 to 65 light years) across - would be hard to hide, ”the scientist adds.
At the moment - this is the only study of its kind, and it has not yet been published in any scientific journal with the name, but received the approval of astrophysicists who gathered at the conference.
The work was carried out using data from the Gaia Space Observatory of the European Space Agency, which is mapping stars and their movements inside the Milky Way. Thanks to this mission, scientists were able to compile the most comprehensive at the current moment catalog of stars of our galaxy, which also included the GD-1 stellar flux.
She supported her analysis with data collected using the Multi-mirror Telescope located in Arizona, which showed which stars move in the direction of the Earth and which, on the contrary, move away. This helped her identify the stars that are actually part of the GD-1 stream, in which the second hole and a previously unseen region were discovered.
Bonaka notes that he intends to continue work on the search for an unknown source of the most powerful gravity, which punched a hole in the stellar flow, but the main purpose of its research is to map dark matter clusters scattered throughout the Milky Way.
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