How far beyond the plane of a spiral galaxy will the magnetic field extend? Astronomers know that spiral galaxies have magnetic fields, but the extension of magnetic fields is blurred.
In NRAO's giant radio telescope, it was found that magnetic fields can extend thousands of light-years perpendicular to the direction of the galactic disk.
The spiral galaxy NGC 5775
This image of the spiral galaxy NGC 5775, which faces the side, has the potential for columnar magnetic field lines to be ubiquitous in spiral galaxies. Similar to the iron filings around magnets, radiation from electrons can also be used to track the magnetic field lines of galaxies, which orbit almost at the speed of light.
The pinnate streaks in the figure are generated using this trajectory in the VLA data. Visible-light images from the Hubble Space Telescope show pink star-generating regions. The stellar wind also appears to have played a major role in forming and extending the magnetic field.