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Dark matter mysteries revealed by two new galaxies

What To Know

  • Astronomers have recently identified two new satellite galaxies of the , a that could provide valuable clues about the that makes up about 85% of the matter in the universe.
  • By combining the distribution of dwarf galaxies observed by this telescope with its footprint in the sky, the researchers then estimate that there could be up to 500 satellite galaxies around the Milky Way, far more than the 220 predicted by initial simulations.
  • The team of researchers now plans to use more telescopes to get a more complete view of the night sky so that they can confirm or correct current estimates of the number of dwarf galaxies surrounding the Milky Way.

Astronomers have recently identified two new satellite galaxies of the Milky Way, a discovery that could provide valuable clues about the dark matter that makes up about 85% of the matter in the universe.

Understanding dark matter

There black matter remains a cosmological mystery, because it does not interact with light or the ordinary matter that makes up stars, planets, and living beings. Its potential interactions with these elements are so weak that they go unnoticed. Therefore, believe that it could be composed of unknown particles or tiny primordial , remnants of the Big Bang. However, dark matter interacts with gravity by influencing the motion and dynamics of light and ordinary matter. This allows scientists to deduce its presence and determine that large galaxies are surrounded by vast halos of dark matter. These halos are thought to extend far beyond galactic disks and halos of visible matter. The standard model of , known as the lambda cold matter model (ΛCDM), predicts that these dark matter halos played a crucial role in the of galaxies. In the , they formed gravitational wells in which gas and dust gathered to form stars and galaxies. Eventually, these halos coalesced to form large galaxies like the Milky Way.

The problem of counting dwarf galaxies

The ΛCDM model suggests that there should be hundreds of satellite galaxies around the large galaxies. For example, simulations predict that our neighbor, the galaxy ofAndromedashould be surrounded by about 500 satellite galaxies. However, astronomers have only observed 39 of them. For the Milky Way, some simulations based on the standard model of cosmology indicate that it should be surrounded by about 220 dwarf galaxiesHowever, there are only about sixty of them, evolving at maximum distances of 1.4 million light years, the best known of which are the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC), hence the interest in this discovery.

Replace the problem with another

A team of researchers has announced that they have identified two new satellite galaxies, named Sextans II and Virgo IIIthanks to the Subaru telescope, located in Hawaii. The discovery of these two objects therefore contributes to rebalancing the accounts a little. However, the results of these could in reality pose a new problem for cosmologists: the total number of dwarf galaxies could be much higher than expected. Indeed, Subaru’s observations do not cover the entire night sky. By combining the distribution of dwarf galaxies observed by this telescope with its footprint in the sky, the researchers then estimate that there could be up to 500 satellite galaxies around the Milky Way, far more than the 220 predicted by initial simulations. In other words, this could mean that scientists have replaced the problem of the lack of dwarf galaxies with a new problem, this time involving too many dwarf galaxies.
milky way dwarf galaxies dark matterThe newly discovered Virgo III dwarf galaxy with its constituent stars outlined in white. Credits: NAOJ/Tohoku University

Continue research

To test this hypothesis, the astronomers studied the distribution of satellite galaxies around the Sculptor Galaxy (NGC 253), recently discovered by amateur astronomer Giuseppe Donatiello. They found that the distribution of these satellite galaxies was uneven, suggesting a “favored direction.” If a similar direction exists around the Milky Way and the Subaru telescope is pointing in that direction, it could inflate the estimates based on Subaru’s observations. The team of researchers now plans to use more powerful telescopes to get a more complete view of the night sky so that they can confirm or correct current estimates of the number of dwarf galaxies surrounding the Milky Way. The Vera C. Rubin Observatory in Chile will be used for this purpose starting next year. The team’s results were published June 8 in the Publications of the Astronomical Society of Japan.

Laurie Spongerro
Laurie Spongerro
I am Laurie, passionate about science and space. For years, I have dedicated my time to exploring and sharing the latest advancements and discoveries in these fascinating fields. Through my articles on Thenextfrontier.net, I invite you to dive into a universe rich with innovations and mysteries, with the goal of making science accessible and captivating for everyone. Join me on this scientific and technological adventure on Thenextfrontier.net.

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