New Delhi: An international research team has produced the largest magnetic map of the universe to date, revealing an invisible cosmic web that shapes
how galaxies form and evolve. The map is five times larger than all previous efforts combined, and charts intergalactic magnetism to better understand how matter moves through space, and how the universe has evolved over billions of years. The project utilised the ASKAP radio telescope in Western Australia, located at Inyarrimanha Ilgari Bundara on Wajarri Yamaji Country. The astronomical instrument can scan vast areas of the sky and at greater depth than older generation instruments.
The new map, named SPICE-RACS is based on the principle that light twists as it travels through magnetic fields. By measuring this distortion in the radio signals detected by ASKAP, researchers can identify the precise location and relative strength of these fields. The team reprocessed original data from the Rapid ASKAP Continuum Survey to collect rotation measures from nearly four million galaxies, constructing a full picture. The approach was deemed technologically impossible before being attempted. The dataset represents the first major advancement in cosmological magnetic data in twenty years, and finally provides comprehensive coverage of the southern sky.
Magnetic Map to improve in future
The new detail allows scientists to investigate the material between nearby stars, and analyse how magnetic fields affect galactic-scale interactions, such as those between the Milky Way and the Magellanic Clouds. It also offers a pathway to determining when magnetic fields first appeared in the universe. The maps and underlying digital assets are freely accessible to the global scientific community, allowing independent replication and new insights. The Polarisation Sky Survey of the Universe’s Magnetism (POSSUM) collaboration will continue producing enhanced maps using ASKAP over the coming years. Furthermore, the SKA telescopes under construction in Australia and South Africa will begin operations later in the decade, allowing for charting cosmic magnetism in even finer detail. A paper describing the research has been accepted for publication by the Publications of the Astronomical Society of Australia.
