A Radio Eye in the Outback
In the remote Western Australia, 36 identical antennas work together as a single instrument: the Australian Square Kilometre Array Pathfinder, or ASKAP. Each antenna dish measures 12 meters in diameter and stands three stories tall. They are distributed across an area approximately 6 kilometers in diameter, an arrangement that allows astronomers to achieve high-resolution images of the sky. The facility is located at Inyarrimanha Ilgari Bundara, the Murchison Radio-astronomy Observatory, a location chosen for its extreme "radio quietness". This legally protected zone is shielded from the radio-frequency interference generated by modern electronics, which would otherwise drown out the faint cosmic signals astronomers seek.
The telescope's function is to conduct rapid and comprehensive surveys of the southern sky. Its primary technology is a set of novel "radio cameras," officially known as phased array feed (PAF) receivers, positioned at the focus of each dish. These PAFs give each antenna an enormous instantaneous field of view of about 31 square degrees. This wide view allows ASKAP to map the sky far faster than conventional radio telescopes. One of its first major projects, the Rapid ASKAP Continuum Survey (RACS), mapped the entire southern sky in just 300 hours, cataloging three million galaxies, one million of which had never been seen before.
Charting Galaxies and Cosmic Bursts
ASKAP's design is optimized for several large-scale scientific investigations. One is the Evolutionary Map of the Universe (EMU), a project to conduct a deep census of radio sources across the southern sky. EMU is expected to detect around 70 million galaxies, providing a vast dataset to study how galaxies form and evolve. Another project is WALLABY (Widefield ASKAP L-band Legacy All-sky Blind surveY), which maps the distribution of neutral hydrogen gas. This survey helps astronomers understand the composition of galaxies, their interactions, and the structure of the cosmic web. WALLABY is expected to detect hundreds of thousands of galaxies.
The telescope is also an instrument in the study of Fast Radio Bursts (FRBs). These are powerful, millisecond-long flashes of radio waves originating from deep space. ASKAP's wide field of view makes it exceptionally good at detecting these fleeting events. Because it is an array of multiple dishes, it can use the tiny differences in the signal's arrival time at each antenna—fractions of a billionth of a second—to locate the burst's origin galaxy with high precision. This capability has helped trace these mysterious bursts back to their homes, billions of light-years away. The raw data generated by the array is immense, flowing at a rate of 100 trillion bits per second, which is processed in near real-time at the Pawsey Supercomputing Research Centre in Perth.