Setonix and ASKAP fire up to image ancient stellar explosion

Ever heard the saying “it takes a village” when it comes to a task that is so big and complex, that it requires many hands, heads and hearts to have it completed? Well, that is what most science and astronomy is like these days - many people, teams, instruments, technology and resources pooled together to achieve some of the most extensive capabilities required, to understand the complexities and wonders of our Universe. 

Last week, we saw this in action - with the release of a brilliant new, highly detailed image of a supernova remnant, captured by ASKAP, and processed by one of Australia’s newest supercomputers - Setonix. 

ASKAP (owned and operated by Australia’s national science agency, CSIRO) is an array of 36 dish antennas, located on Wajarri Yamatji Country out at the Murchison Radio-astronomy Observatory (MRO) about 800 kilometres northeast of Perth. It is one of the most sensitive radio telescopes in the world and can peer into the cosmos at radio wavelengths, capturing the roaring hearts of distant galaxies, supernova remnants, and the regular periodic ticking of pulsars. 

This time around, it captured an image of the supernova remnant G261.9+5.5 - an expanding shell of ejected material and debris from the violent detonation of a massive star that happened a long time ago. As the shockwave and debris sweep into the expanding interstellar medium, it causes matter to emit in electromagnetic radiation, including in the radio regime. 

But ASKAP’s work is only half the job of producing such a magnificent image - the rest relies on what happens downstream, as the data from the telescope is passed to supercomputers to run the processing. And here’s where one of Australia’s newest supercomputers steps in. 

Setonix (currently in its first phase of deployment) is a new, state-of-the-art HPE Cray EX supercomputer, hosted at the Pawsey Supercomputing Research Centre, that features 64 cores, allowing it to deliver on double the computing power of its predecessor, Magnus - which is also housed at Pawsey. 

Phase two of the supercomputer is currently making its way to Australia and will be installed after Magnus and Zeus (two other supercomputers located at the Pawsey Centre), are decommissioned.

The Pawsey Centre, located in Kensington Perth, was established for exactly these kinds of reasons. A purpose-built facility, it takes data from instruments like ASKAP (which produce extremely large volumes of the stuff) and processes them in record time - allowing Australian scientists to have the most up-to-date output from the telescope in the shortest amount of time. In turn, this gives our local space community a very competitive edge above some of the other global, large-scale instruments. 

Dr Pascal Elahi, Pawsey’s supercomputing applications specialist, said deploying this first phase of Setonix has increased the computing power of the Pawsey Centre by 45 per cent.

“Processing data from ASKAP’s astronomy surveys is a great way to stress-test the Setonix system and see what is possible.”

While Setonix is ramping up to full operations so is ASKAP, which is currently wrapping up a series of pilot surveys and will soon undertake even larger and deeper surveys of the sky. Setonix will be used to process the data collected by ASKAP.

Dr Wasim Raja, a researcher on CSIRO’s ASKAP team, said the supernova remnant’s dataset was selected to test the processing software on Setonix, given the challenges involved in imaging such a complex object.

“The speed at which we reproduced our current workflows is a good sign as we look to improve and optimise them to fully exploit Setonix’s capabilities.

“Setonix’s large, shared memory will allow us to use more of our software features and further enhance the quality of our images. This means we will be able to unearth more from the ASKAP data.

“We look forward to working together with colleagues at the Pawsey Centre, who were pivotal to this success, as we continue integrating the complete processing pipelines on Setonix,” said Dr Raja.

Setonix is named after one of Western Australia’s favourite animals - the quokka (Setnoix Brachyurus), with the supercomputer itself covered by the works of Wajarri Yamatji visual artist Margaret Whitehurst, which was inspired by the stars that shine over the Wajarri country in Western Australia’s mid-west. 

The new supercomputer is part of the longer-term strategy, and larger investment in Australian science infrastructure, as the science community ramps up towards the construction and eventual activation of the SKA telescope, towards the end of this decade.

We acknowledge the Wajarri Yamatji as the traditional owners of the Murchison Radio-astronomy Observatory site, where ASKAP is located.