Galaxy that acts as cosmic magnifying glass discovered
Posted on Aug 01 2014 | IANS
Washington, Aug 1 : Using NASA's Hubble Space Telescope, astronomers have unexpectedly discovered the most distant galaxy that acts as a cosmic magnifying glass.
Seen as it looked 9.6 billion years ago, this monster elliptical galaxy breaks the previous record-holder by 200 million years.
"When you look more than nine billion years ago in the early universe, you do not expect to find this type of galaxy lensing at all," said lead researcher Kim-Vy Tran of Texas A and M University in College Station.
It is very difficult to see an alignment between two galaxies in the early universe.
These "lensing" galaxies are so massive that their gravity bends, magnifies, and distorts light from objects behind it, a phenomenon called "gravitational lensing".
"Finding one in such a small area of the sky is so rare that you would normally have to survey a region hundreds of times larger to find just one," Tran said.
The team suspects the lensing galaxy continued to grow over the past nine billion years, gaining stars and dark matter by cannibalising neighbouring galaxies.
Recent studies suggest these massive galaxies gain more dark matter than stars as they continue to grow.
The newly discovered distant lensing galaxy will eventually become much more massive than the Milky Way and will have more dark matter, too, researchers noted.
The findings appeared in The Astrophysical Journal Letters.