It’s not due to begin operating until 2013, but astronomers from around the world are already lining up to use CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP). In fact, the first five years of ASKAP’s operation are already booked out, with ten major international Survey Science projects looking for pulsars, measuring cosmic magnetic fields, studying millions of galaxies, and more.

ASKAP might be a demonstrator project for the much larger SKA, but it will also be a cutting-edge telescope in its own right. The 36-dish ASKAP features a new ‘focal plane array’ technology that gives it a huge 30° field of view. “So instead of concentrating on one small patch, we can cover the whole sky in a fairly short space of time,” says Simon Johnston, ASKAP project scientist.

A large dynamic range—the difference between the strongest and weakest signals picked up—is another advantage. “We’re aiming to get a dynamic range 10 to 100 times better than CSIRO’s current flagship telescope, the Compact Array,” says Simon.

“It’s important to stress the international nature of the science that will be done on ASKAP,” says Phil Diamond, Director of CSIRO Astronomy and Space Science. “That’s a big thing for us, because the SKA is an international project. We want to ensure that ASKAP is international in scope, not just Australian only.”

Mapping magnetism reveals cosmic history

One international team waiting to use ASKAP is planning the largest-ever survey of magnetic fields in the Universe—revealing new details of cosmic history.

“Magnetic fields are important because they basically tell gas in the Universe how to move,” says Bryan Gaensler, an astrophysicist at The University of Sydney. “And because gas is the ingredient that makes galaxies, stars and planets, it’s vital we know magnetism’s influence if we’re to understand how the Universe has evolved.”

Magnetic fields in distant space can’t be measured directly. Astronomers have to rely on the effect magnetism has on the polarisation of electromagnetic waves (such as radio waves and light waves) reaching their telescopes.

Bryan heads the team that will use CSIRO’s ASKAP to conduct the survey, which is called POSSUM—the POlarisation Sky Survey of the Universe’s Magnetism. ASKAP will be the ideal facility when it comes online in 2013.

“Previous studies covered either a big part of the sky but not to a great depth in space, or probed to a great depth but only over a small area. POSSUM will go both wide and deep,” says Bryan. “We’ll improve on the current best survey by a factor of 100.”

Studying the effects of cosmic magnetism, however, is only one part of the challenge. Astronomers still don’t have a full understanding of where all the magnetism came from in the first place. Bryan hopes POSSUM will help to answer that question too.

PHOTO 1: THE FIRST ASKAP DISH BEING ERECTED IN FEBRUARY 2010. CREDIT: DAVE DEBOER, CSIRO

PHOTO 2: BRYAN GAENSLER IS SURVEYING THE UNIVERSE’S MAGNETIC FIELDS. CREDIT: THE UNIVERSITY OF SYDNEY.

CSIRO Astronomy and Space Science
Dr Simon Johnston, Tel: +61 (2) 9372 4573, Simon.Johnston@csiro.au, www.atnf.csiro.au/projects/askap/index.html

Sydney Institute for Astronomy, University of Sydney
Professor Bryan Gaensler, Tel: +61 (2) 9351 6053, bryan.gaensler@sydney.edu.au, askap.org/possum