2005/02/28 by B. M. Gaensler, C. Kouveliotou, J. D. Gelfand +16 · 1 citation
Physics and Astronomy · #astro-ph
paper · pdf · doi:10.1038/nature03498
published as Nature 434 (2005) 1104-1106 · 13 pages, including 2 colour & 1 b/w figures, and supplementary methods. Uses nature.sty. Nature, in press (submitted 18 Jan 2005, accepted 17 Feb 2005). Corrected epoch of uv data in Figure 1
arxiv created 2005/05/22 · arxiv updated 2009/12/01
Soft gamma repeaters (SGRs) are "magnetars", a small class of slowly spinning neutron stars with extreme surface magnetic fields, ~1015 gauss. On 2004 December 27, a giant flare was detected from the magnetar SGR 1806-20, the third such event ever recorded. This burst of energy was detected by a variety of instruments and even caused an ionospheric disturbance in the Earth's upper atmosphere recorded around the globe. Here we report the detection of a fading radio afterglow produced by this outburst, with a luminosity 500 times larger than the only other detection of a similar source. From day 6 to day 19 after the flare from SGR 1806-20, a resolved, linearly polarized, radio nebula was seen, expanding at approximately a quarter the speed of light. To create this nebula, at least 4x1043 ergs of energy must have been emitted by the giant flare in the form of magnetic fields and relativistic particles. The combination of spatially resolved structure and rapid time evolution allows a study in unprecedented detail of a nearby analog to supernovae and gamma-ray bursts.