Jennifer Foreshew | November 11, 2008
A SYDNEY researcher has developed technology to enable astronomers to get sharper pictures of distant galaxies.
The new system reduces distortion
As a PhD student at Sydney University's School of Physics, Brendon Brewer developed a computer program to help understand gravitational lensing.
This 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.
The 25-year-old's de-lensing program allows the gravitational lens to be used as a natural telescope, but without the distortion.
"The idea is that you see an image on the sky and there are some indications that the image is not what it really looks like if it has been lensed by an object in front," said Mr Brewer, currently involved in statistics research at the University of NSW.
"You can remove the light of the foreground galaxy so all you are seeing is the distorted image of the background galaxy, and then the program answers the question of what possible sources, when lensed, would look like that."
The program, which relies on Bayesian statistics, works in a similar way to photographic de-blurring technology.
"We have used it to re-analyse some previous observations and we were able to get better results than were previously obtained. They had sharper resolution in the reconstruction," Mr Brewer said.
"We found we were able to get a reconstruction of where carbon monoxide is located in a very distant galaxy that is a quasar."
First observed by radio telescopes, carbon monoxide gas exists under the same conditions as molecular hydrogen and, as it is easier to detect, can be used as a tracer or proxy to locate star formation regions.
"When people observe these things and they want to know what the source is like intrinsically, not lensed, we can help."
Mr Brewer said he had applied for permission to look at a large number of lensed galaxies using the Gemini Observatory, which has telescopes in Hawaii and Chile.
Sydney University's Geraint Lewis, who supervised Brewer for his PhD studies, said the software would be applied to new gravitational lens systems, which were currently being developed.
"One of the big problems in astronomy is that we get our images from the sky and they are degraded, so they are either blurred by the atmosphere or by the telescope and noise is added," Associate Professor Lewis said.
The program offered a new approach to reconstructing images from gravitational lens systems to pull out the most information from imperfect data, he said.