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

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关键词: RAY REPEATER SGR1900+14;    SOFT GAMMA-REPEATERS;    RADIATIVE MECHANISM;    SGR 1806-20;    PULSAR;    SGR-1900+14;    AFTERGLOWS;   

DOI  :  10.1038/nature03498

来源: SCIE

【 摘 要 】

Soft gamma-ray repeaters (SGRs) are 'magnetars', a small class of slowly spinning neutron stars with extreme surface magnetic fields, B approximate to 10(15) gauss (refs 1-3). On 27 December 2004, a giant flare(4) was detected from the magnetar SGR 1806-20 (ref. 2), only the third such event recorded(5,6). This burst of energy was detected by a variety of instruments(7,8) and even caused an ionospheric disturbance in the Earth's upper atmosphere that was recorded around the globe(9). 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(10). 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 of the speed of light. To create this nebula, at least 4 x 10(43) ergs of energy must have been emitted by the giant flare in the form of magnetic fields and relativistic particles.

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