An expanding radio nebula produced by a giant flare from the magnetar SGR 1806-20

B. M. Gaensler, C. Kouveliotou, J. D. Gelfand +16

Soft gamma repeaters (SGRs) are "magnetars", a small class of slowly spinning neutron stars with extreme surface magnetic fields, ~10^15 gauss. On 2004 December 27, a giant flare w…