Scientists studying the Andromeda galaxy discovered that the globular clusters inside it really were born somewhere outside of it. They form a structure that is called the “dark stream”. It is the remnants of one or more smaller star systems that our neighbor “ate”.
“Dark Stream” in the neighboring galaxy
The Andromeda galaxy, or M31, is the closest large spiral galaxy to us, similar to the Milky Way. A few years ago, scientists came to the conclusion that some globular clusters in its vicinity were formed outside of it.
These clusters form a colossal formation, which scientists have called the Dulais structure, which translates from Welsh as “dark stream”. The article, the preprint of which is posted on the website arxiv.org tells about the formation of this object.
According to experts, the Dulais structure is the remnants of one or more star systems that were torn to pieces and absorbed by Andromeda in the past. Thus, it is a “cosmic cannibal”.
Andromeda galaxy “ate” its neighbors
There is no news for scientists that large galaxies evolve by “eating” smaller ones. Not all scientists agree on such a picture of the world, but, for example, it is known from the Milky Way that it has definitely absorbed other star systems during its history.
However, scientists are still not sure how many torn-to-shred galaxies are the remains of the Dulais structure. It can be either one system destroyed in some stages, or several. Modeling shows that Andromeda experienced at least two active periods of “cannibalism” in the past.
One of them occurred about 5 billion years ago, that is, shortly before the Solar System was formed. The second one is more ancient, it occurred 8-10 billion years ago. Scientists note that at that time the universe was much smaller and the matter in it was located closer than now.
Evolution of the Universe
Scientists want to continue observing the “dark stream” in the Andromeda galaxy in order to understand how common such “cannibalism” really is and how important a role it plays in the evolution of galaxies.
After all, in addition to tearing apart their neighbors, galaxies are also growing due to the constant influx of gas from outer space. So far, we have judged how these two processes relate mainly to our own galaxy.
However, being inside it, it is difficult to notice all the details. The Andromeda galaxy, which is located at a certain distance from us, but not too far away, is the best object for research.
According to Рhys.org
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