Scientists at the Harvard-Smithsonian Center for Astrophysics are at a loss. Something "unknown, dense, invisible through telescopes and consisting, most likely, not of ordinary matter, like a bullet pierced and made giant holes inside our Milky Way galaxy." The evidence for this was presented at the conference of the American Physical Society in Denver (USA) by the astrophysicist Anna Bonaka.
The holes she discovered in the Milky Way are located in the longest stellar stream, GD-1. They are groups of stars moving along the orbit of galaxies. Once they were a small globular cluster or a dwarf galaxy, and now they fly apart.
Under normal conditions, the researcher notes, the flow should stretch more or less in a line with a single gap where the globular cluster was originally located before the stars began to fly in different directions. But Bonaka has demonstrated that GD-1 has a second gap. Interestingly, this second rupture has torn edges - as if something huge broke through the stream not so long ago and dragged away some of the stars under the influence of a tremendous force of gravity.
The scientist believes that, of course, it is impossible to exclude 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 flare or radiation from its accretion disk. At the same time, the astrophysicist notes, most large galaxies have only one supermassive black hole in the center.
Another suggestion of the scientist is a large clot of dark matter. However, Bonaka notes that the object is not necessarily completely, it is 100% dark matter.
At the moment, this is the only study of its kind, and it has not yet been published in any scientific journal with a name, but has received the approval of the astrophysicists gathered at the conference.
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The work was carried out using data from the Gaia space observatory of the European Space Agency, which is engaged in mapping stars and their movements within the Milky Way. Thanks to this mission, scientists were able to compile the most complete catalog of stars in our galaxy to date, which also included the stellar stream GD-1.
She backed up her analysis with data collected with the Multi-Mirror Telescope, located in Arizona, which showed which stars are moving towards the Earth, and which, on the contrary, are moving away. This helped her identify stars that are indeed part of the GD-1 stream, in which the second hole and previously unseen region was discovered.
Bonaka notes that he is going to continue work on the search for an unknown source of the most powerful gravity, which punched a hole in the stellar stream, but the main purpose of her research is to map the clumps of dark matter scattered throughout the Milky Way.
Nikolay Khizhnyak