Some 163,000 lightsYears of the Milky Way A much smaller and older galaxy: Tucana II, named after the constellation of tropical birds in which it is located. Sitting on the periphery of our galaxy’s gravity, Tucana II provides researchers with an opportunity to understand the formation of the oldest galactic structures in the universe.
Now, a team of astronomers I found evidence of an extended halo of dark matter around the galaxy. Their search was Published Today in Nature Astronomy.
“We know [dark matter] “There is because in order for galaxies to remain bound, there has to be more matter than we clearly see, from starlight,” said Anerod Chitty, an astronomer at MIT., On a phone call. This led to the hypothesis of dark matter as an element that held galaxies together. Without it, the galaxies that we know, or at least the things in their outskirts, would fly away. “
The dark matter halo is a gravitational region A bound substance in space. (The dark matter halo of the Milky Way It extends even further The The fan that makes up the visible objects of our galaxy). The team found that the limits of gravity for Tucana II ranged between three and Five times larger than previously thought Even some of the oldest galaxies will contain halos of dark matter.
Tucana II happens to be the most chemically primitive galaxy we currently know, which means that some of its stars have a very low mineral content (The heaviest elements in the universe were produced at a later time). The team realized that Tucana II had a dark matter aura when observations of stars in that region of the sky revealed that the stars were moving side by side.
“If you look at the region of the sky where the galaxy is, you will not actually see the star clusters or their extra densities,” Chetti, Which is Lead author of the modern paper, He said. “It is only when you look at their velocities and realize that they are a group of stars moving at the same speed that you realize that there is a galaxy out there.”
As co-author Anna Freibel, who is also an astronomer at the Massachusetts Institute of Technology, said in a university press release, the Tucana II motion worm is like “shower water flows into a sewer.” Persuasively, some of the galaxy’s oceanic stars are older than the stars closest to the galactic center. The team hypothesizes that Tucana II may have been the result of a previous galactic merger, a cosmic clash that saw one primitive galaxy eat up another, resulting in stars of different origins appearing in the same galaxy.
Whether or not Tucana II’s origin theory is correct, a similar collision will surely be in its future. Since it lies within the gravitational realm of the more massive Milky Way, in the end, the relatively small galaxy will be swallowed up by our own.
While astronomers know how to spot dark matter halos, they still don’t know exactly what dark matter is. Besides finding halos around galaxies, researchers are also looking for the identity of dark matter in them Mysterious signals from neutron stars And in the form Small theoretical black holes.