Jan 6 (): Astronomers say they were surprised by the discovery of a group of dwarf galaxies dancing in a ring around the much larger Andromeda Galaxy. They say observation of small galaxies are locked in a strange dance around a larger one presenting a challenge to current theories of how all galaxies form and evolve.
Under the leadership of Rodrigo Ibata, of the Observatoire Astronomique de Strasbourg, in France, a team of astronomers made the discovery about dwarf galaxies using observations collected by the Pan-Andromeda Archaeological Survey. This survey studied about the Andromeda and Triangulum galaxies, also known as M31 and M33. Canada-France-Hawaii telescope in Hawaii were used for this survey.
Andromeda is the largest galaxy of the Local Group, which consists of the Andromeda Galaxy, the Milky Way, the Triangulum Galaxy and about 30 other smaller galaxies.
Andromeda galaxy is about 2.5 million light years away and it is the closest giant galaxy to Milky Way galaxy. As it is the closest galaxy to our galaxy, it allows the astronomers to examine structures that we cannot view in our galaxy.
During the survey, 27 dwarf galaxies were detected in a disc of 1.3 million light years in diameter around Andromeda. Fifteen of the galaxies aligned along a single plane and 13 of those 15 appeared to ”co-rotate” in the same direction.
This alignment in a vast, thin disc could change scientists’ understanding of how galaxies form, researchers said this week. Although the astronomers are still not sure what this means, they believe the discovery could reshape the understanding of how galaxies are formed.
Astronomers earlier believed that all of the pancake-shaped “disk galaxies,” like our Milky Way, had been still for the last 8 billion years — more than half of the universe’s 13.7-billion-year existence. But after this new survey, astronomers are reconsidering how our own galaxy transformed over time.