Astronomers from the University of Cambridge have discovered nine dwarf galaxies orbiting the Milky Way. This is the first time that so many neighboring dwarf galaxies have been found at once.
The astronomers say that the latest discovery was made with the help of the Dark Energy Survey, which is mapping the southern sky.
Dr. Sergey Koposov, lead author of the study, says that the research team was not expecting to find so many galaxies in a small part of space. The research team is confident about the identity of at least three new dwarf galaxies. However, the rest can either be dwarf galaxies or even globular clusters. The scientists explain that globular clusters are usually visually similar to dwarf galaxies but are not glued together with dark matter.
The astronomers suggest that further studies are required to confirm the identity of the remaining six galaxies. The latest discovery will still give stargazing opportunities to many sky-watchers.
Dwarf galaxies are usually the smallest of all the galactic structures and can contain only around 5,000 stars. The Milky Way contains an estimated 200 billion to 400 billion stars.
The new discovery, the scientists say, will also be significant in understanding more about dark matter. Scientists estimate that dwarf galaxies can have a dark matter content of about 99 percent, which makes them optimal for testing different models of dark matter.
"Dwarf satellites are the final frontier for testing our theories of dark matter," said Dr. Vasily Belokurov from the Institute of Astronomy, who is also a co-author of the study. "We need to find them to determine whether our cosmological picture makes sense."
Belokurov says that it was quite surprising to find such a cluster and that they were not hoping to find "such treasure." The closest of the latest dwarf galaxies is about 97,000 light-years and located in the Reticulum constellation. The farthest dwarf galaxy is about 1.2 million light-years away and is in the Eridanus constellation.
Scientists estimate that there are hundreds of dwarf galaxies that are circling the Milky Way. However, they are difficult to find as they are quite faint. So far, only about 30 dwarf satellite galaxies have been identified.
The study was published in The Astrophysical Journal.
