3 mins read 13 Apr 2022

Major Upgrade to Central MWA Processing Brain

The Murchison Widefield Array (MWA) has undergone a digital brain transplant to significantly improve its signal correlator. This technological overhaul has vastly boosted the array’s processing capability and will majorly enhance the telescope’s resolving power. 

”The Outlier” is one of the 256 MWA aperture array tiles. It is located 1.5km from the centre of the array. Credit: Natasha Hurley-Walker / MWA Collaboration & Curtin University.

The MWA radio telescope in Western Australia has recently upgraded the ‘brains’ of its operation - the signal correlator - and in doing so has further cemented its role as one of the key low-frequency precursors for the joint Australian and South African Square Kilometre Array (SKA). This responsibility will be complemented by the neighbouring ASKAP (Australia SKA Pathfinder) telescope which is similarly designed to scope out the skies at slightly higher radio frequencies.  But before we get into what this technical development means for the future, we should take a minute to recall how radio telescopes work. 

Whether we’re talking about the robotic spider-like dipole antennas of the MWA or parabolic dish antennas like ASKAP or the illustrious CSIRO Parkes Murriyang telescope, the basic premise is the same: a radio antenna detects electromagnetic (EM) radiation - at radio frequencies (RF) - and converts the EM wave power into an electrical voltage. 

The received RF signals are then digitally split up into spectral channels which need to be correlated - or ‘cross-correlated’ for telescopes with multiple receivers - in order to create images. This correlator component is arguably one of the most important elements of a radio telescope but can also be its biggest limitation.    

This high-level schematic shows the path of a signal from array tile to data archive. It demonstrates how a limited capacity correlator could hold up the flow of data during the first phase of MWA operations. Credit: S. J. Tingay et al. 2013, PASA.

When it first began observing the radio skies in 2013 the MWA’s correlator was only able to simultaneously process data coming from half of the array’s 4,096 antennas, which are grouped into 256 tiles spread over several kilometres - each forming their own effective array of digitally combined signals. With the newly upgraded MWAX computing system, the MWA is finally able to work at full strength as it can now compute up to 900 trillion floating-point calculations per second (known as FLOPS); a capability held by only the most advanced supercomputers about a decade ago.

“MWAX was always the next step in the MWA’s evolution, which turned out to be more of a giant leap, really,” said Curtin University Project Officer Mia Walker, “I think it’s the best example of how we are achieving our goal to provide the highest quality data and service to the MWA Collaboration.”  

Side-by-side 185 MHz radio images of the Fornax A galaxy. The left and right are images from the MWA’s first and second phases of operation, respectively. With MWAX we can expect a further increase in angular resolution. Credit: R. B. Wayth et al. 2018, PASA.

The ability to utilise the full array of antennas means that astronomers observing with the MWA will be able to see the radio sky with greater angular resolution, as more antennas produce additional information with which to produce more detailed images. These high-resolution images are expected to produce impressive scientific findings since the MWA has a very wide field of view - several hundred times the angular size of the Moon on the sky - with which to observe the Universe.  

Prior to this MWAX upgrade - which was carried out using a million-dollar grant from the Australian Federal Government administered by Astronomy Australia Ltd (AAL) - the MWA collaboration has already produced a number of exciting scientific results including observations of magnetised cosmic filaments, a previously undetected pulsar, and a mysterious new radio object that astronomers have yet to identify. 


We acknowledge the Wajarri Yamatji people as the traditional owners of the CSIRO Murchison Radio-astronomy Observatory site where the MWA is located.

Photo of the new MWAX server. Credit: MWA Collaboration & Curtin University.