VLA Reveals Distant Galaxy’s Magnetic Field – National Radio Astronomy Observatory
https://public.nrao.edu/news/vla-reveals-magnetic-field/
With the help of a gigantic cosmic lens, astronomers have measured the magnetic field of a galaxy nearly five billion light-years away.
The achievement is giving them important new clues about a problem at the frontiers of cosmology — the nature and origin of the magnetic
fields that play an important role in how galaxies develop over time.
The scientists used the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) to study a star-forming galaxy that lies
directly between a more-distant quasar and Earth. The galaxy’s gravity serves as a giant lens, splitting the quasar’s image into two
separate images as seen from Earth. Importantly, the radio waves coming from this quasar, nearly 8 billion light-years away, are
preferentially aligned, or polarized.
“The polarization of the waves coming from the background quasar, combined with the fact that the waves producing the two lensed images
traveled through different parts of the intervening galaxy, allowed us to learn some important facts about the galaxy’s magnetic field,”
said Sui Ann Mao, Minerva Research Group Leader for the Max Planck Institute for Radio Astronomy in Bonn, Germany.
