We're a step closer to understanding how energy is spread across the Universe, with the most detailed map of intergalactic magnetism ever produced. It's more than five times larger than all earlier studies combined.
Researchers from Australia’s national science agency CSIRO and the SKA Observatory (SKAO) have produced the detailed images using the ASKAP radio telescope.
“For the first time, we can investigate fine details of the material between nearby stars, and study a huge number of distant galaxies,” says lead researcher Dr Alec Thomson, commissioning scientist with the SKAO.
We obviously can't see magnetic fields, so it can be easy to underestimate their role in how they shape our world and the space beyond it. Without Earth's invisible geomagnetism, solar winds would ultimately render the planet uninhabitable.
The new imagery has been produced by the CSIRO’s ASKAP radio telescope, at Inyarrimanha Ilgari Bundara in Western Australia, where it monitors the sky's radio signals as part of the Rapid ASKAP Continuum Surveys (RACS). In 2020, it produced the largest and fasted radio sky survey in history.
Now, the new map, known as SPICE-RACS, is built on the foundation that light twists as it travels through a magnetic field. So measuring the degree of twisting as captured by ASKAP, the scientists could locate these fields and measure their strength.
“We collected rotation measures from every galaxy detected in RACS – nearly four million galaxies – and reprocessed this original data from ASKAP to retrieve the full picture,” Thomson says.
Our understanding of the Universe is heavily dependent on the technology we have to survey it – as a majority of space is invisible to the naked eye.
“For the past 20 years we have been working with essentially the same data set, which didn't even cover the southern sky," says Professor Naomi McClure-Griffiths, SKAO’s Chief Scientist. "Now, we can finally answer some big questions with a much better picture of the Universe’s magnetic structures.
“With the information we now have on magnetic fields throughout the Universe, we can study things like how magnetic fields affect the galactic-scale interaction of our own Milky Way and its neighbours, the Magellanic Clouds," she adds. "We can even potentially find the answer to questions like when did magnetic fields first appear in the Universe? We had once thought it would be impossible to answer these questions. I’m excited to say that is no longer the case."
The CSIRO researchers have also made there data open access, encouraging scientists around the world to conduct their own research with it.
“Our data is accessible to anyone, whether it be for something unique in their own work or to replicate something tested already – an important part of the scientific process,” says CSIRO astronomer Dr Tim Galvin. “The data for this project is already being used by many research teams to produce new insights.
"By having these resources freely available, we’re supporting the continued advancement of our collective understanding of the Universe," he adds.
CSIRO's data portal is a valuable resource for scientists – or anyone who loves to spend a few hours down a good rabbit hole.
And while these maps are remarkable achievements, the international team of researchers, known as the Polarisation Sky Survey of the Universe's Magnetism (POSSUM) collaboration, promises even they're just the beginning.
The research has been accepted – but yet to be peer-reviewed – by the Publications of the Astronomical Society of Australia.
Source: CSIRO
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