SYDNEY, July 6 (Xinhua) -- Australian scientists have captured a radio signal emitted before Earth's solar system was born, revealing a new galaxy 5 billion light-years away, local media reported on Monday.
Using a ground-breaking radio telescope in remote Western Australia, the Australian scientists identified a wisp of cosmic radio waves coming from the galaxy PKS B1740-517 in the direction of the southern constellation of "Ara."
Astronomers are salivating over the discovery because the 5- billion-year-old signal - although tiny, it clearly stood out in the ASKAP data - shows Australia's new Square Kilometer Array Pathfinder project's (ASKAP) 36 dishes will be able to detect galaxies other telescopes can't.
"This catch shows we're going to bag a big haul of galaxies," research leader James Allison of Australia's scientific body CSIRO said.
Astronomers can detect a galaxy from its hydrogen gas even when its starlight is faint or hidden by dust.
The signal detected carried the 'imprint' of cold hydrogen gas - the raw material for forming stars and plentiful in most galaxies - that it passed through on its way to earth.
The gas absorbs some of the emission, creating a tiny dip in the signal.
"At many observatories, this dip would have been hidden by background radio noise, but our site is so radio quiet it stood out clearly," Allison said.
University of Sydney Professor of Astrophysics, Elaine Sadler - a member of the research team - said ASKAP looked at relatively unexplored parts of the radio spectrum 700 to 1,800 megahertz.
"This means we'll be able to detect hydrogen gas deeper in space and, thanks to ASKAP's wide field of view, also over a much larger volume than we could before," Sadler said. "We'll be hunting for galaxies that are five to eight billion years old, a time-span that represents a fifth of the universe's history."
While many radio telescopes succumb to radio interference - unwanted signals that clutter up the spectrum - the ASKAP site is exquisitely radio quiet.
By studying galaxies 5 to 8 billion years old, astronomers hope to understand why galaxies were making stars 10 times faster 10 billion years ago then they do now.
