A team of astronomers led by Miguel Aragón, from the National Autonomous University of Mexico, discovered a curious feature in the Milky Way: our galaxy is too big for its “cosmic wall”, composed of the flattened arrangement of galaxies found around it.
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In addition to galaxies, the walls also contain regions called “voids”. These areas seem to unite the galaxies in a kind of pancake-like structure, thus forming a flattened group of them. This environment, called the “Local Plate”, influences how the Milky Way and nearby galaxies rotate on their own axes.
The discovery came from an Reviews with simulations of the IllustrisTNG project, which models the physical universe. When they simulated an area of about a billion light-years and millions of galaxies, they found that only a “special” part of them, with mass similar to that of the Milky Way, could be inside the wall.
Joe Silk, co-author of the study, explains that the Milky Way has no mass or type that makes it special, and that there are several other similar spiral galaxies. “But she’s rare if you consider the surroundings,” he noted. “What we found is that the other walls of galaxies, like the Local Plate, often have a galaxy as massive as the Milky Way,” he said.
The study did not consider Andromeda, the Milky Way’s largest neighbor, but the authors acknowledge that it may be necessary to consider the local environment to study the Milky Way, rather than assuming that the proportion of our galaxy is common, and that it occurs in a place like in the universe.
As the simulations were made focusing on the Milky Way in a “wall”, future works may consider more galaxies in the local group. Still, the researchers note that the environmental context can help explain some phenomena not yet understood, such as the unusual configuration of galaxies around Andromeda.
The article with the results of the study was published in the journal Monthly Notices of the Royal Astronomical Society.
Source: Monthly Notices of the Royal Astronomical Society; Via: Royal Astronomical Society