Cosmic superlens gives telescopes a boost

The ultimate telescope upgrade lies about 3.5 billion light-years away in the constellation Sculptor.

Abell 2744 (below) is a galaxy cluster whose tremendous mass — equivalent to 2 quadrillion suns — turns it into a gravitational lens that bends and magnifies light from distant objects. This effect allows astronomers to peer farther into space than any telescope can do alone. By studying images of far-flung galaxies revealed by Abell 2744, researchers created a map (above) that charts how the cosmic lens manipulates light from the far side of the universe.

The map spans just over 3 million light-years on a side. Areas in red magnify light most strongly, up to 30 times; blue regions introduce less amplification. Gray contours trace the directions along which images of remote galaxies are elongated. Since the lensing ability depends on the cluster’s mass, the map also charts the distribution of stars, gas and invisible dark matter, physicist Xin Wang of the University of California, Santa Barbara and colleagues report online April 9 at arXiv.org.

Abell 2744 has already proven its worth. The Hubble Space Telescope, assisted by the cluster’s gravity, recently spied one of the most distant galaxies known. Three highly magnified copies of an inconspicuous red blob show a galaxy at a redshift of 9.8, which corresponds to when the universe was just 500 million years old — almost 9 billion years before Earth existed.