Part 163,000 aotrom-years from the Sweet Way much smaller, much older galaxy: Tucana II, so named for the bird-like tropical constellation in which it sits. Sitting at the edge of our galaxy’s gravitational pull, Tucana II allows researchers to understand the composition of the earliest galactic structures in the universe.
Now he’s on a team of astronauts find evidence of a Halo of dark matter expanded around the constellation. They had their research published today in the journal Nature Astronomy.
“We know [dark matter] is that for galaxies to be connected, there has to be more than we can clearly see, from starlight, ”said Anirudh Chiti, an astronomer at the Massachusetts Institute of Technology, in a phone call. “That led to the idea of a dark substance that acts as an ingredient that holds galleries together; without it, galaxies we know of, or at least the material at the periphery, would simply fly apart. ”
A halo of dark matter is the area of grazing a connected subject in space. (Dark halo the Milky way extends much further an pinwheel which makes up the visible material of our galaxy). The team found that the marginal boundaries of Tucana II are between three and five times more than previously expected, shows that even some of the oldest galleries will have halos of dark cases.
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Tucana II happens to be the most chemically predominant galaxy we know at the moment, meaning that some of its stars have a very low metal content (the heaviest elements of the universe were realized later in time). The team realized that Tucana II had a dark subject when scenes of stars in that region of the sky showed that the stars were moving in unison.
“If you just look at the area of the sky where the constellation is, you don’t really see a cluster or too many stars,” Chiti said. who is the lead author of the recent paper, said. “Only when you look at their speeds and realize that a galaxy is a group of stars moving at the same speed. ”
As study co-author Anna Frebel, who is also an astronomer at MIT, put it in a university press release, the movement at Tucana II is like “bath water going down the drain. Interestingly, some galaxy fringe stars are older than stars closer to the galactic center. The team speculates that Tucana II may be the result of a previous galactic union, a cosmic galaxy that saw one primitive galaxy eaten by another, resulting in stars of different sources in the same galaxy.
Whether that theory about the origin of Tucana II holds true, a similar tragedy is certain in the future. Being within the gravity range of the much larger Milky Way, the rather petite galaxy will eventually be swallowed by ours.
Although astronomers know how to see halos of dark matter, they do not yet know what a dark matter is. In addition to finding its halos around galaxies, researchers are also looking for the identity of a dark matter within. secret signals from neutron stars and in shape small, theoretical black holes.