Astronomers discover magnetic field of galaxy 11bn light years away

6 Sep 2023

Image: ALMA (ESO/NAOJ/NRAO)/J Geach et al

Lead author of the study based on ALMA observations, James Geach, said that “no other telescope” could have achieved the feat.

Astronomers have made the furthest ever detection of a galaxy’s magnetic field using the ALMA telescope in Chile.

“Many people might not be aware that our entire galaxy and other galaxies are laced with magnetic fields, spanning tens of thousands of light years,” says Prof James Geach of the University of Hertfordshire, who led the study published today (6 September) in Nature.

Geach and the team used observations made by the Atacama Large Millimeter/submillimeter Array telescope to detect a magnetic field so far away that its light took more than 11bn years to reach us. This means the magnetic field was present when the universe was just 2.5bn years old.

Many astronomical bodies in the universe, from planets and stars to entire galaxies, have magnetic fields of their own. But so far, we have only been able to map and study magnetic fields of galaxies close to us – leaving a gap in our understanding of their evolution.

“We actually know very little about how these fields form, despite their being quite fundamental to how galaxies evolve,” added Enrique Lopez Rodriguez, a researcher at Stanford University and co-author of the study.

A partner of the European Southern Observatory (ESO), ALMA was used by Geach and the team to discover the magnetic field which is not much different from the ones observed around galaxies close to the Milky Way. “No other telescope could have achieved this,” Geach said.

Interestingly, its magnetic field is about 1,000 times weaker than the Earth’s. However, it is significantly more spread out than ours, extending over more than 16,000 light years.

Geach said that the discovery indicates that magnetic fields spanning entire galaxies can form rapidly while young galaxies are still growing and gives us “new clues” about how galactic-scale magnetic fields are formed.

The team believes that intense star formation in the early universe could have played a role in accelerating the development of the fields. Moreover, these fields can in turn influence how later generations of stars will form.

Co-author Dr Rob Ivison, an ESO astronomer, said that the discovery opens up “a new window onto the inner workings of galaxies, because the magnetic fields are linked to the material that is forming new stars.”

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Vish Gain is a journalist with Silicon Republic