Using the ALMA (Atacama Large Millimeter/submillimeter Array) radio interferometer, we detected the magnetic field of a galaxy identified as 9io9, more than 11 billion light-years from Earth. The importance of this discovery lies mainly in the fact that this result provides new clues about the formation of magnetic fields on a galactic scale.
The galaxy as seen by ALMA. Credit: ALMA (Eso/Naoj/Nrao)/J. Geach et al.
Galaxies also have magnetic fields
Galaxies, including the Milky Way, are pervaded by magnetic fields. These fields extend over tens of thousands of light-years. These fields are fundamental to understanding the evolution of the galaxies themselves, but we know very little about them. How early in the life of the Universe and how quickly magnetic fields form in galaxies, for example, we do not know.
What we have discovered by observing 9io9
Thanks to ALMA, a group of researchers has discovered an already fully formed magnetic field in a distant galaxy, with a structure that is similar to the one observed in galaxies close to us. Specifically, the magnetic field is about a thousand times weaker than Earth's, but extends over sixteen thousand light-years. The observation of a fully developed magnetic field at this early stage in the history of the universe suggests that such fields can form rapidly during the growth of young galaxies. It is thought that intense star formation in the early Universe may have played a role in accelerating the development of the fields.
How the magnetic field was discovered
Galaxies are filled with grains of dust that, in the presence of a magnetic field, tend to align themselves and thus emit polarized light (light waves that oscillate in a particular direction rather than at random). Astronomers therefore looked for light emitted by 9io9 dust to detect it.
Post a Comment