Researchers have discovered eleven runaway galaxies that were flung from their home clusters due to gravitational turbulence.
In the past, researchers have discovered 24 runaway stars that were flung out of their galaxies. However, researchers from the Harvard-Smithsonian Center for Astrophysics and Moscow State University have discovered 11 galaxies that have been tossed out of their galactic cluster homes to forever wander through intergalactic space.
Igor Chilingarian, an astronomer working with the Harvard-Smithsonian Center for Astrophysics and Moscow State University, and the lead author of the study, said, “These galaxies are facing a lonely future, exiled from the galaxy clusters they used to live in.”
The researchers originally set out to identify new members of a class of galaxies, which are known as compact elliptical. These are miniature groups of stars that are larger than star clusters but smaller than typical galaxies. In their study, they observed nearly 200 previously unknown compact elliptical. However, they also discovered 11 galaxies, which were isolated and found far away from any clusters.
The researchers stated that the discovery was unexpected, because the previous 30 compact ellipticals that had been found were all located in clusters. Experts believed that isolated compact galaxies came from larger galaxies, which had been stripped of most of their stars during interactions with larger galaxies, and thus they should be found near those larger galaxies. However, not only where these newfound galaxies isolated, they were also found to be moving faster than those in clusters.
“The first compact ellipticals were all found in clusters because that’s where people were looking. We broadened our search, and found the unexpected. This is the same phenomenon, but working on a different scale, a slingshot effect, when during a three-body encounter the lightest body flies away from the system,” added Chilingarian.
The researchers added that these runaway galaxies are actually helping the compact galaxies survive. Without them the compact galaxies would be torn apart by their massive hosts.
The findings were published in the Science journal.