Researchers Identify Farthest Gravitational Lens Ever Discovered

Researchers have identified the farthest gravitational lens ever discovered.

A gravitational lens refers to a celestial object that amplifies the light emitted by an even farther object, acting as a natural telescope astronomers can use to peer even deeper into space than they would otherwise be able. The phenomenon is also helpful in better understanding the nature of the amplifier by allowing scientists to directly measure the mass of the object bending the light. When the two objects directly align, a perfect circle of light called an Einstein ring is created, representing a projected and magnified image of the distant light source.

According to lead author the study, Arjen van der Wel from the Max Planck Institute for Astronomy, "The discovery was completely by chance."

The researcher was reviewing observations from a previous project when he stumbled upon a "decidedly odd" galaxy.

"It looked like an extremely young galaxy, but it seemed to be at a much larger distance than expected," he said. "It shouldn't even have been part of our observing [program]!"

Eager to find out more, he began studying images taken using Hubble. The object looked like an old galaxy in these pictures, but boasted irregular features that, the researcher guessed, suggested a gravitational lens.

By combining the images and removing the haze from the lensing galaxy's stars, Van der Wel was able to identify a nearly perfect Einstein ring.

According to the researcher, the lensing mass is so far away that the light, after deflection, has to travel 9.4 billion years to reach Earth -- a new record.

The discovery presents a new set of problems, however.

Not only are gravitational lenses theoretically extremely rare, but the magnified object has been identified as a young starbursting dwarf galaxy producing stars at a fantastic rate. The odds that such a peculiar galaxy should be gravitationally lensed is miniscule, and yet this is the second one researchers have identified. In other words, either astronomers are wildly lucky, or starbursting dwarf galaxies aren't as rare as currently believed.

"This has been a weird and interesting discovery," Van der Wel said. "It was a completely serendipitous find, but it has the potential to start a new chapter in our description of galaxy evolution in the early Universe."