Using NASA's Hubble and Chandra telescopes, astronomers discovered the most crowded galaxy closest to earth, which is 10 billion years old and located at a distance of only 54 million light years away.
The newly discovered compact galaxy M60-UCD1, is home to a large number of stars. According to researchers, this may be the densest galaxy closest to the Earth. Researchers hope that this new discovery will provide clues to its role in the galactic evolutionary chain.
Astronomers believe that the galaxy is over 10 billion years old and is located near the massive elliptical galaxy NGC 4649, which is only 54 million light years away from our planet. The galaxy weighs more than 200 million times the weight of the Sun, according to observations made with the W.M. Keck Observatory 10-meter telescope in Hawaii.
The entire mass of the galaxy is spread across a radius of only 80 light years. The density of this newly discovered galaxy is 15,000 times greater that the density of the Milky Way. This means stars in M60-UCD1 are 25 times closer to each other than stars in the Milky Way.
"Traveling from one star to another would be a lot easier in M60-UCD1 than it is in our galaxy, but it would still take hundreds of years using present technology," said Jay Strader of Michigan State University in Lansing. Strader is the lead author of the paper about the research, which was published Sept. 20 in The Astrophysical Journal Letters.
Researchers also found that the elements heavier than helium and hydrogen in the stars of the galaxy were the same as the sun.
"The abundance of heavy elements in this galaxy makes it a fertile environment for planets and, potentially, for life to form," said co-author Anil Seth of the University of Utah.
What intrigued astronomers even more about the galaxy was the presence of a bright X-ray source at its center. Researchers speculate that the source of this bright light could be a giant black hole weighing about 10 million times the mass of our sun.
Researchers are keen to learn whether the galaxy was born in the "ultra-compact" way that it now is or did it get its density over time due to the formation of more stars. They also speculate that if the source of the bright light is indeed a black hole then it could be because of a previous collision between M60-UCD1 and a neighboring galaxy as black holes are not found in huge star clusters.
"We think nearly all of the stars have been pulled away from the exterior of what once was a much bigger galaxy," said co-author Duncan Forbes of Swinburne University in Australia. "This leaves behind just the very dense nucleus of the former galaxy, and an overly massive black hole."
Researchers also believe that if the galaxy has been stripped of some of its stars then the galaxy was originally 50 to 200 times more massive than it is now. The stripping could have taken place long ago and M60-UCD1 may have been stalled at its current size for several billion years.
