ESA: Herschel ATLAS project

The light from a distant galaxy (red) is bent and magnified by the presence of a foreground galaxy (blue), in a process called gravitational lensing.

The background galaxy is observed as a distorted image (pink) at far-infrared and sub-millimetre telescopes. (Credit: NASA/JPL-Caltech)

Home of Herschel ATLAS

Cosmic zoom lens allows astronomers to see galaxies otherwise hidden from us when the Universe was only a few billion years old.

This provides key insights into how galaxies have changed over the history of the cosmos.
“What we’ve seen so far is just the tip of the iceberg,” says Loretta Dunne, co-leader of the Herschel-ATLAS survey and an astronomer at the University of Nottingham.

“Wide area surveys are essential for finding these rare events and since Herschel has only covered one thirtieth of the entire Herschel-ATLAS area so far, we expect to discover hundreds of lenses once we have all the data. Once found, we can probe the early Universe on the same physical scales as we can in galaxies next door.

ESA Herschel Mission

“The data from the area of sky used for this work has now been released to the astronomical community and we hope that now astronomers not directly involved in H-ATLAS will dive into this data set and exploit the wealth of science which is bursting to be done with it.”

A century ago Albert Einstein showed that gravity can cause light to bend. The effect is normally extremely small, and it is only when light passes close to a very massive object such as a galaxy containing hundreds of billions of stars that the results become easily noticeable.

When light from a very distant object passes a galaxy much closer to us, its path can be bent in such a way that the image of the distant galaxy is magnified and distorted.

These alignment events are called “gravitational lenses” and many have been discovered over recent decades, mainly at visible and radio wavelengths.