The Small Magellanic Cloud is a dwarf galaxy that is merging with the main body of the universe. There is a foreground cluster at the right. The last major merger of the universe was with a dwarf system about 10 billion years ago, according to the new H3 Survey of stars. The Harvard-Smithsonian Center for Astrophysics has a credit.
The description of how galaxies evolve is one of the features of modern cosmology. Nowhere in the universe can we see this more clearly than in our own Milky Way. The Sagittarius dwarf galaxy, which is less than 1% of the stellar mass of a normal spiral galaxy, is being disrupted. Two dwarfs, the Large and Small Magellanic Clouds, are falling towards us. The effects of prior mergers are marked by streams of globular clusters. The positions and motions of stars in the stellar halo can be used to record even more ancient mergers. The merger of the dwarfs with the large neighboring galaxy, called Andromeda, is expected to take another five billion years.
In order to make a precise three-dimensional map of the Milky Way, the Gaia was launched with the goal of surveying 1% of its 100 billion stars. The team used the results of the Gaia survey and a new survey of the outer reaches of our galaxy with the 6.5m MMT telescope. The evidence shows that a single dwarf galaxy merged with the Milky Way about 10 billion years ago. The stars in the inner halo give an idea of what is left of the object. It was not certain if GSE collided with our galaxy head-on, or if it traveled around the galaxy before merging.
The astronomer compared the stellar ages and compositions with a set of numerical simulations to address the questions. They show that GSE contained half a billion stars, but did not approach the Milky Way in a straight line. Roughly 50% of the Milky Way's current stellar halo and 20% of its dark matter halo descend from it. The stars in the Milky Way are 13 billion years old and may have been captured by the galaxy after it formed. The entire growth of the Milky Way can be accounted for with the completion of this study.
The research was published in a journal.
The Astrophysical Journal has more information about Rohan P. Naidu and his research on the Last Major Merger of the Milky Way with the H3 Survey. There is a book titled "10847/1538-4357/ac2d2d".
The Astrophysical Journal has information.
Our galaxy's most recent major collision was retrieved fromphys.org on January 7, 2022.
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