Ancient galaxies newly discovered in southern sky
A concentrated effort by Australian telescopes and the Hubble Space Telescope on a tiny, dark patch of the southern sky has led to the discovery of thousands of previously unknown galaxies.
Preliminary resuts will be released today from the ten-day period of observation in October, when the Hubble and ground-based telescopes were focused simultaneously on a patch of sky called the Hubble Deep Field South.
The tiny piece of sky was carefully chosen for astronomers to learn more about distant galaxies. Like the Hubble Deep Field, another small patch in the northern sky which was observed in late 1995, it contains no bright stars to drown out the light from objects much further away. Unlike its northern counterpart, however, the Hubble Deep Field South was picked because it had a quasar -- the bright centre thought to be the central 'engine' of a distant galaxy.
Astronomers at the Anglo-Australian Observatory sifted through their photographic records of the whole southern sky until they found a likely quasar, 10 billion light-years away. "The quasar acts like a lighthouse in the distance," said the Observatory's Dr Chris Tinney. "It helps you see anything in its path."
While the high-resolution Hubble detected and photographed the galaxies in the path of the quasar's beam, the Anglo-Australian Observatory could analyse their spectra for more information about their shape and size.
From the results, astronomers hope to learn about the life cycles galaxies go through, from creation to old age.
"What you're seeing are the embryonic stages of very old galaxies," said Dr Tinney. "When you're looking at distant galaxies you're looking back in time -- right back to the first ten percent of the age of the Universe."