Astronomers say the Hubble Space Telescope has observed the farthest example of a lensing galaxy -- galaxies so large they can act like cosmic "magnifying glasses" -- discovered to date.
At 9.6 billion light years from the Earth, it may be the most distant lensing galaxy known to science, NASA said in announcing the discovery.
Lensing galaxies have such intense gravitational field they can warp and magnify the light coming from even more distant galaxies that astronomers might not otherwise be able to detect.
The newly discovered galaxy, observed by both Hubble and the Keck Observatory in Hawaii, has magnified the light from an even more distant galaxy sitting 10.7 billion light years from Earth.
It's unusual to find a lensing galaxy so far away and yet so perfectly aligned with another behind it to reveal it, the researchers say.
"When you look more than 9 billion years ago in the early universe, you don't expect to find this type of galaxy lensing at all," explains lead researcher Kim-Vy Tran of Texas A&M University. "It's very difficult to see an alignment between two galaxies in the early universe."
The object visible thanks to the cosmic lens is a small spiral galaxy in the throes of a rapid spurt of star birth.
The magnifying galaxy, located in a galaxy cluster known as IRC 0218, breaks the previous record for the most distant such galaxy by 200 million light years, the researchers say.
It's a massive galaxy considering the age at which we see it, and is among the most luminous in its surrounding cluster, they say.
"There are hundreds of lens galaxies that we know about, but almost all of them are relatively nearby, in cosmic terms," says study first author Kenneth Wong of the Academia Sinica Institute of Astronomy & Astrophysics in Taiwan. "To find a lens as far away as this one is a very special discovery because we can learn about the dark-matter content of galaxies in the distant past. By comparing our analysis of this lens galaxy to the more nearby lenses, we can start to understand how that dark-matter content has evolved over time."
Invisible dark matter is thought to account for most of the universe's mass.
The distant galaxy today is probably very similar to massive galaxies closer to Earth in terms of its dark matter content, but since we are seeing it as it was 9 billion years ago it is providing a fascinating glimpse into the cosmic past and the process of galaxy formation, the researchers say.
