NASA's Hubble spots distant galaxy

NASA's Hubble Space Telescope has spotted a tiny, faint galaxy - one of the farthest galaxies ever seen through a giant cosmic magnifying glass over 13 billion light years away.

This galaxy offers a background to the early formative years of the universe and may just be the tip of the iceberg, said a study.

"This galaxy is an example of what is suspected to be an abundant, underlying population of extremely small, faint objects that existed about 500 million years after the big bang, the beginning of the universe," said Adi Zitrin of California Institute of Technology in Pasadena and study leader.

The discovery was made using the lensing power of the massive galaxy cluster Abell 2744, called Pandora's Cluster, which produced three magnified images of the same, faint galaxy.

These clusters are so massive their gravity deflects light passing through them, magnifying, brightening, and distorting background objects in a phenomenon called gravitational lensing, noted the study.

The galaxy measures merely 850 light years across - 500 times smaller than our Milky Way galaxy - and is estimated to have a mass of only 40 million suns.

Given its small size and low mass, the tiny galaxy is rapidly evolving and efficiently forming stars, pointed out Zitrin.

The team spotted the galaxy's gravitationally multiplied images using near-infrared and visible-light photos of the galaxy cluster taken by Hubble's wide field camera three and advanced camera for surveys.

They performed the colour-analysis technique and took advantage of the multiple images produced by the gravitational lens to independently confirm the group's distance estimate.

"These measurements imply that, given the large angular separation between the three images of our background galaxy, the object must lie very far away," Zitrin explained.

"The discovery is telling galaxies as faint as this one exist, and we should continue looking for them and even fainter objects, so that we can understand how galaxies and the universe have evolved over time," concluded Zitrin.

The team's results appeared in the Astrophysical Journal Letters.