Astronomers measured the magnetic field of a record distant object

Astronomers measured the magnetic field of a record distant object

Using light that has been reaching us for more than 11 billion years, scientists have just measured the most distant magnetic field. This is the field of the 9io9 galaxy, which appears to us as it was only 2.5 billion years after the Big Bang. The construction of magnetic field lines will help astronomers understand the evolution of early galaxies during the birth of the universe.

“Many people may not know that our entire galaxy and other galaxies are dotted with magnetic fields reaching tens of thousands of light years,” says astrophysicist James Geach from the University of Hertfordshire (UK). “This discovery gives us new insights into how galactic-scale magnetic fields are formed.”

Magnetic fields are widespread in the universe. They usually arise as a result of the movement of conductive material, which converts kinetic energy into magnetic energy, which is called the dynamo effect. For example, the Earth’s magnetic field is created due to the movement of fluid inside it.

Galactic magnetic fields are thought to be generated similarly. A galaxy rotates, and the charged gas inside it also rotates. This motion maintains the galactic magnetic field, but it is much weaker than around Earth or the Sun. Thus, the magnetic field of the Milky Way is measured in the range of 25-60 microgauss, while at the surface of the Earth it is from 0.22 to 0.67 gauss.

However, we do know how galactic magnetic fields arise in general. Are they created as a result of a downward process inherited from the wider universe in which they are formed? Are they inherited from larger-scale processes? The discovery of 9io9’s magnetic field provides some clues.

The image of the galaxy was magnified by the presence of a space-time-warping mass in the foreground, allowing Geech and his colleagues to measure the polarization of its light.

Infrared image 9io9. 9io9 is a red arc distorted and magnified by the gravity of the bright foreground object in the center.

Judging by the analysis of the light, the magnetic field of 9io9 turned out to be similar to the magnetic field of nearby galaxies. It even showed comparable strength – 500 microgauss and below. This is about 1000 times weaker than the Earth’s magnetic field.

This indicates that the magnetic field formed quickly while the galaxy was still growing, so galactic magnetic fields are closely related to the material from which new stars are formed.

The authors believe that star formation, which often occurs at breakneck speed in the early universe, may contribute to the acceleration of the growth and development of galactic magnetic fields. In turn, magnetic fields can influence further star formation.

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