The magnetic fields in the halo of NGC 4631 show magnetic fields that reverse direction in a regular fashion. A magnetic dynamo could explain this behaviour, never before seen in a galaxy’s halo. See https://public.nrao.edu/news/giant-magnetic-ropes/ for more information.
A study of spiral galaxies seen edge-on has revealed that “halos” of cosmic rays and magnetic fields above and below the galaxies’ disks are much more common than previously thought. See the spectacular image and read the full story at: