Magnetic Fields Halfway Across the Cosmos

Aug 28, 2017

UW Astronomers were part of a team that measured the magnetic field strength in a far-away galaxy, using a newly developed technique that involves gravitational lensing. The work was performed by badger alumna Sui Ann Mao from the Max Planck Institute for Radio Astronomy in Bonn, Germany, along with her team that included Professor Ellen Zweibel from UW Madison. By using the different paths light from a background quasar (a brightly shining black hole even farther away than the galaxy), they were able to tease out how the polarization of the light was changed by the gas inside the galaxy, releaving the strength of the mangetic field in this young galaxy. The light left the galaxy five billion years ago, showing that large scale, organized magnetic fields were created quickly, through the so-called dynamo mechanism. "This measurement provided the most stringent tests to date of how dynamos operate in galaxies", says Ellen Zweibel.

Read more in the UW press release.

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