Andromeda shredded and consumed a massive galaxy about two billion years ago

Scientists have long understood that during the course of cosmic evolution, galaxies become larger by consuming smaller galaxies. The evidence of this can be seen by observing galactic halos, where the stars of cannibalized galaxies still remain. This is certainly true of the Andromeda galaxy (aka M31, the closest neighbor of Earth) that has a mbadive and almost invisible star halo that is larger than the galaxy itself .

result of hundreds of smaller fusions. But thanks to a new study by a team of researchers from the University of Michigan, it now seems that the Andromeda halo is the result of the cannibalization of a mbadive galaxy about two years ago. billion years. The study of the remains of this galaxy will help astronomers understand how disk galaxies (such as the Milky Way) evolve and survive large fusions

. The study titled "The Fusion most important of the Andromeda galaxy about 2 billion years ago ". appeared recently in the scientific journal Nature. The study was conducted by Richard D • Souza, postdoctoral researcher at the University of Michigan and at the Vatican Observatory; and Eric F. Bell, Professor Arthur F. Thurnau at the University of Michigan

In this image, the Andromeda galaxy shreds the large M32p galaxy, which ultimately leads to M32 and a giant halo d & # 39; stars. Credit: Richard D & # 39; Souza. Credit: AAS / IOP / Wei-Hao Wang

Using computer models, Richard D & Souza and Eric Bell were able to piece together how a once mbadive galaxy (named M32p) disrupted and eventually merged with Andromeda. From their simulations, they determined that M32p was at least 20 times larger than any galaxy that fused with the Milky Way during its lifetime.

M32p would have been the third largest member of the local group of galaxies, after the Milky Way and the Andromeda galaxies, and so was something of a "long lost brother". However, their simulations also indicated that many smaller companion galaxies merged with Andromeda over time. But for the past, the Andromeda halo is the result of a single mbadive fusion. As explained by Souza in a recent statement to the Michigan News Press:

"It was a moment" eureka ". We realized that we could use this information from the stellar halo external image of Andromeda to derive the properties of the largest of these jagged galaxies.Staronomists study the local group – the milky way, Andromeda and their companions – for so long.It was shocking to realize that the Milky Way had a big brother, and we never knew it. "

This study will not only help astronomers understand how galaxies like the Milky Way and Andromeda have developed through mergers over a long-standing mystery – this is how the Andromeda satellite galaxy (M32) was formed. According to their study, D'Souza and Bell believe that M32 is the surviving center of M32p, which is what remained after its spiral arms were removed.

Messier 31 (The Andromeda Galaxy), with Messier 32 and Messier 110 Credit: Wikisky

"M32 is a nutty," Bell said. "Although it looks like a compact example of an old elliptical galaxy, it actually has a lot of young stars – it's one of the most compact galaxies in the world." There's no other galaxy like this. "According to Dr. Souza and Bell, this study could also alter the traditional understanding of the evolution of galaxies. astronomy, conventional wisdom says that large interactions would destroy disk galaxies and form elliptic galaxies.

But if Andromeda actually survived an impact with a mbadive galaxy, this would indicate that this is not the case The timing of the merger may also explain the results of recent research that indicated that two billion years ago, the disk of the Andromeda galaxy was thickened, leading to an explosion in star formation As Bell explained:

"The galaxy 's. Andromeda, with a spectacular explosion of star formation, would have been so different 2 billion years ago. When I was at the graduate school, it was said that understanding how the Andromeda galaxy and its M32 satellite galaxy were formed would go a long way toward Clarification of the mysteries of the formation of galaxies. "

to study other galaxies and determine the most mbadive fusions they have undergone, which could enable scientists to better understand the complicated process that leads to the growth of galaxies and how mergers affect This knowledge will certainly be useful when it comes to determining what will happen to our galaxy when it merges with Andromeda in a few billion years

Further Reading: Michigan News

] By Matt Williams

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Matt Williams is the curator of Universe Today's Guide to Space.He is also an independent writer, a science fiction writer and a Taekwon- Do. He lives with his family on the island of Vancouver, in beautiful British Columbia.