Coke bottle vision solved by young Sydney astronomer

20 October 2008

Astronomers will have a much clearer picture of distant galaxies thanks to a cutting edge technology which was developed by a talented young astronomer at the University of Sydney.

Brendon Brewer was a 22-year-old PhD student at the University's School of Physics, when he developed a computer program to solve gravitational lensing, one of the major problems of modern astronomy.

Gravitational lensing is a phenomenon sometimes referred to by astronomers as a 'natural telescope', which can bend and stretch images into different shapes making it difficult to clearly observe distant galaxies.

Until now working out a way to use gravitational lensing effectively has eluded scientists. "Imagine trying to view an object through the bottom of a Coke bottle and you've got an idea of what we've been up against," said Brendon.

"When one galaxy sits in front of another it distorts the galaxy behind making it difficult to see the structure of distant galaxies, which can provide us with necessary clues about how galaxies formed in the early universe," Brendon said. "I've developed a 'de-lensing' program that still allows the gravitational lens to be used as a natural telescope but without the distortion."

So far the program has enabled astronomers to sharply focus on the most distant galaxies. "We've recently used the technique to map star-forming regions in an early universe galaxy which also shows clouds of carbon monoxide gas. We've also produced some of the sharpest images ever of a lensed galaxy - something that's a first."

Astronomers know that for star formation molecular hydrogen is needed, but it is very difficult to see. First observed by radio telescopes carbon monoxide gas exists under the same conditions as molecular hydrogen and, as it's easier to detect, can be used as a tracer or proxy to determine the star formation regions.

Using Brendon's program astronomers have located where the molecular hydrogen is and how the different parts are moving in a distant galaxy that also hosts a quasar in its core.

"What Brendon has achieved is significant. This is quite an advance on what is already out there. We were very conscious of designing this program in the best possible way so as to extract as much information about distant, early universe galaxies as possible," said Brendon's supervisor, Associate Professor Geraint Lewis.

"This has been a highly fruitful scientific collaboration between Brendon Brewer and Professor Geraint Lewis from the University of Sydney, and Dr Dominik A. Riechers Hubble Postdoctoral Fellow at Caltech, Pasadena, CA, USA," said Brendan.

Contact: Jake O'Shaughnessy

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