Australian SKA precursor telescopes
To prepare for the SKA, two new-generation telescopes have been developed in Australia. Located at the Murchison Radio-astronomy Observatory are our ASKAP radio telescope, and the Curtin University-led Murchison Widefield Array.
ASKAP is a radio telescope with a fast survey capability to map large areas of space in a single pointing.
ASKAP combines advanced wide-field receiver technology with powerful digital signal processing systems and a supercomputer to map cosmic radio signals. The telescope consists of 36 dish antennas connected by optical fibre that work together as an array. Each ASKAP antenna can look in several different directions at once thanks to our phased array feed receivers.
How does ASKAP work?
By combining the signals from 36 smaller antennas, we can make high-resolution images at a fraction the expense of building an extremely large dish with the same eye for detail. The wide-angle receiver fitted to each ASKAP antenna uses multiple receptor elements to look in several directions simultaneously. Images are reconstructed from raw data using a supercomputer in Perth and can be downloaded from a public archive.
Why is it significant?
ASKAP was designed to enable a new kind of radio astronomy, using rapid mapping to conduct all-sky surveys that can be used by astronomers worldwide. Most of the objects detected by the telescope are galaxies outside the Milky Way. By cataloguing millions of these radio galaxies, we will study the structure and evolution of the universe.
ASKAP answers large-scale questions by taking a big-picture view. Its first survey mapped 83% of the sky in a few months, pinpointing millions of galaxies and improving on the sensitivity and resolution of previous surveys that took years to complete. ASKAP is also sensitive to an important part of the radio spectrum that traces hydrogen gas. This is the most abundant element in the Universe and fuels stars like the Sun.
ASKAP’s rapid survey capabilities are opening our eyes to the dynamic Universe by providing a way to study changes over days and weeks, instead of years. It can even search for radio bursts that last for fractions of a second by scanning the raw data before images are formed. These capabilities provide astronomers around the world with data that will help us understand the structure and evolution of the Universe better than ever before.
Who is it for?
While CSIRO operates the telescope itself, the amount of data we provide is so large that it creates a global challenge. We collaborate with teams from universities and other institutions around the globe to plan survey strategies, create high-quality maps and archive these for open access.
ASKAP is demonstrating the high-performance processing required to meet the SKA data challenges. Using the Pawsey supercomputer and custom-written software developed at CSIRO, we produce science-ready datasets of many Terabytes for each observation, served to astronomers through ASKAP’s science archive.
The Murchison Widefield Array
The Murchison Widefield Array is a low-frequency radio telescope operating between 80 and 300 MHz. Already delivering first-class science, it is located at the Murchison Radio-astronomy Observatory (MRO) in Western Australia. The MWA is one of three telescopes designated as a Precursor for the SKA. To this end, the MWA was developed by an international collaboration, including partners from Australia, India, New Zealand, and the United States. It became fully operational in 2013. Whilst a precursor to the SKA, it won’t be integrated into the final SKA telescope and will continue to work as an independent resource in its own right.
Science with the MWA
The MWA will perform large surveys of the entire Southern Hemisphere sky and acquire deep observations on targeted regions. Using the MWA, astronomers will pursue four key science objectives. The primary endeavour is the hunt for intergalactic hydrogen gas that surrounded early galaxies during the cosmological epoch of reionization.
The MWA will also provide new insights into our Milky Way galaxy and its magnetic field, pulsing and exploding stellar objects, and the science of space weather that connects our Sun to the environment here on Earth.