If you’ve got kids, they’ve probably asked you why the sky is blue. The answer may not be a high priority for the Square Kilometre Array (SKA), but the biggest radio astronomy telescope project in the world, currently under pre-construction in Australia and South Africa, will be pursuing other important questions in astrophysics.
One hot topic is the origin and formation of “large-scale structures” in the universe. Such structures typically contain dust, gas and hundreds of galaxies which are arranged in strands, sheets and clusters. The bigger these regions are, the more galaxies they attract. Using huge radio telescopes, astronomers can measure the visible and invisible (or “dark”) mass of galaxy clusters, as well as the speed at which they travel through space.
As a partner in the SKA, New Zealand will contribute to some of the largest sky surveys ever done. Dr Melanie Johnston-Hollitt from Victoria University of Wellington and Sydney-based astronomer Professor Ray Norris from CSIRO will embark on this ambitious project, backed by a Marsden Fund grant.
They will use two SKA pre-cursor telescopes to catalogue the characteristics and locations of diffuse radio emissions in galaxy clusters. These emissions will be in the form of cluster relics – believed to be the result of shockwaves left by colliding galaxy clusters, or radio halos – shown by clusters that are merging or disturbed.
Both radio telescopes are located in Western Australia – far from dense populations and their microwaves and mobile phones. The data collected will help answer such fundamental questions as how large-scale magnetic fields in the universe are formed.
Total Funding: $870,000 over 3 years
Researcher: Dr Melanie Johnston-Hollitt, School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140
Telephone: (04) 463 6543