ALMA Reveals Ancient Galaxy's Magnetic Field, Shedding Light on Cosmic Magnetism

Astronomers detected a distant galaxy's ancient magnetic field, which formed when the universe was 2.5 billion years old, offering insights into galactic magnetic field origins.

Galaxies and other astronomical bodies possess extensive magnetic fields, often overlooked by the public. Understanding their origins and evolution remains a fundamental but poorly understood aspect of astrophysics, as prior studies primarily focused on nearby galaxies.

ALMA Sheds Light on Cosmic Magnetism

In collaboration with the European Southern Observatory (ESO), led by Geach, scientists used the Atacama Large Millimeter/submillimeter Array (ALMA) to identify a fully developed magnetic field in a distant galaxy, resembling those seen in nearby galaxies but much weaker, spanning over 16,000 light-years. This discovery sheds light on the rapid formation of galactic-scale magnetic fields during the early stages of galaxy growth.

The team speculates that the intense star formation in the early universe might have accelerated the development of these magnetic fields, and these fields, in turn, could influence the formation of later generations of stars.

ESO astronomer Rob Ivison, a co-author, suggests that this finding provides insight into the inner workings of galaxies, as magnetic fields are linked to star-forming material.

The detection method involved searching for polarized light emitted by dust grains in a distant galaxy named 9io9. When a magnetic field is present, dust grains tend to align, causing the emitted light to become polarized, with light waves oscillating along a preferred direction.

ALMA's ability to detect and map this polarized signal confirmed the presence of a magnetic field in a distant galaxy for the first time, an achievement impossible with any other telescope. The hope is that continued observations of distant magnetic fields will unravel the mystery of their formation in galaxies.

Cosmic Magnetism: Understanding the Hidden Magnetic Universe

Radio astronomy is essential for understanding cosmic magnetism, revealing insights inaccessible through other wavelengths. Magnetic fields exist universally, from interstellar regions to celestial bodies, yet their origins remain enigmatic.

The latest generation of radio telescopes, including SKA pathfinders like LOFAR, MWA, ASKAP, and MeerKAT, offers exceptional capabilities for investigating cosmic magnetism.

These telescopes cover a wide range of radio frequencies and possess high sensitivity, crucial for studying faint and distant celestial objects. The upcoming SKA telescopes are poised to further advance magnetism research, enabling more detailed and comprehensive studies.

Magnetic fields are generated by the movement of charged particles, such as electrons and protons, a phenomenon abundant throughout the Universe. These fields exhibit a vast range of strengths, from trillions of times stronger around the cores of celestial objects like neutron stars to regions between galaxies where magnetic fields may be billions of times weaker than on Earth.

The exploration of diverse cosmic environments is essential for understanding the evolution of magnetism in the Universe. One of the challenges in studying cosmic magnetism is that, unlike stars and galaxies visible through the light they emit, magnetic fields are invisible even to the largest optical telescopes.

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