Astronomers Unveil the Most Detailed Map of the Universe’s Magnetic Fields
The new map, designated SPICE-RACS, is nearly ten times larger than the previous largest survey.
Astronomers have released the most extensive and detailed map of cosmic magnetic fields ever created. Using data from the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope in Western Australia, the map provides unprecedented insight into magnetic fields both within the Milky Way and in distant galaxies.
Map Features and Composition
The SPICE-RACS map is based on observations of approximately 350,000 galaxies. It was created by detecting the twisting of radio waves caused by magnetic fields, a process known as polarisation.
On the map, red colors indicate magnetic fields pointing toward Earth, while blue indicates fields pointing away. Most of the visible structure originates from the Milky Way, with finer details representing more distant regions. The map is five times larger than all previous magnetic field mapping efforts combined.
Background and Methodology
The previous large-scale magnetic field map was produced in 2009.
The new survey is a collaboration between the Polarisation Sky Survey of the Universe's Magnetism (POSSUM) team and the Rapid ASKAP Continuum Survey (RACS) team. ASKAP can observe large sections of the sky simultaneously. The RACS survey identified nearly 4 million galaxies, of which 350,000 were suitable for magnetic field measurements. Data collected shows magnetic fields from the Milky Way and the nearby Magellanic Clouds.
Scientific Context
According to researchers, magnetic fields may influence galaxy formation, star birth, space weather, and cosmic structure. Approximately 99.9% of visible matter in the universe exists in a plasma state, which can be channeled by magnetism.
Studies indicate magnetic fields slow star formation by a factor of three. Co-author Professor Naomi McClure-Griffiths, chief scientist of the SKA Observatory, stated the team is studying how magnetism affects galactic interactions, including the process where larger galaxies siphon gas from smaller ones.
Research Team and Data Access
Lead author Dr. Alec Thomson, a CSIRO scientist at the SKA Observatory, oversaw the project. The data from SPICE-RACS has been made publicly available to the research community to accelerate further studies.
Future Work
The upcoming POSSUM survey, expected to be completed by 2030, is planned to provide a higher-resolution map and allow astronomers to study magnetic fields further back in cosmic history.