Mauna Kea telescopes help find distant galaxy

Advertiser Staff

WAIMEA, Hawai'i — A team of astronomers may have discovered the most distant galaxy in the universe, an estimated 13 billion light-years away and viewed at a time when the universe was in its infancy.

The galaxy was identified by combining the power of NASA's Hubble Space Telescope and the twin W.M. Keck telescopes atop Mauna Kea. The observatories got a boost from the added magnification of a natural "cosmic gravitational lens" in space that further amplifies the brightness of the distant object, according to a Keck news release.

The newly discovered galaxy is likely to be a young galaxy shining during the end of the cosmic "dark ages," the period that ended with the first galaxies and quasars transforming opaque, molecular hydrogen into the transparent, ionized universe that we see today, the release said.

Astronomers estimate that the galaxy, although relatively small, is actively forming stars. It was detected in a long exposure of the nearby cluster of galaxies Abell 2218, taken with the Advanced Camera for Surveys on board the Hubble Space Telescope. This cluster is so massive that the light of distant objects passing through the cluster bends and is amplified, much as a magnifying glass bends and magnifies objects, according to the release.

Such natural gravitational "telescopes" allow astronomers to see extremely distant and faint objects that could otherwise not be seen.

The extremely faint galaxy is so far away, its visible light has been stretched into infrared wavelengths, making the observations particularly difficult. Optical and infrared exposures taken with spectrographs on the 33-foot Keck telescopes were used to confirm the discovery.

The W.M. Keck Observatory is operated by the California Association for Research in Astronomy, a scientific partnership of the California Institute of Technology, the University of California and the National Aeronautics and Space Administration.