Detection of a radio counterpart to the 27 December 2004 giant flare from SGR 1806–20
Detection of a radio counterpart to the 27 December 2004 giant flare from SGR 1806–20
复制标题
DOI：
10.1038/nature03605
复制
发表时间：
2005-02
期刊：
影响因子：
64.8
通讯作者：
P. B. Cameron;P. Chandra;P. Chandra;A. Ray;S. Kulkarni;D. Frail;M. Wieringa;E. Nakar;E. Phinn
中科院分区：
文献类型：
--
作者：
P. B. Cameron;P. Chandra;P. Chandra;A. Ray;S. Kulkarni;D. Frail;M. Wieringa;E. Nakar;E. Phinn
十多年前就已经确定，被称为软γ射线中继器（SGR）的显着高能瞬变位于我们的银河系中，并且起源于具有强磁场（≤ 1015 G）的中子星-所谓的“磁星”。2004年12月27日，SGR 1806-20探测到一个巨大的耀斑，其通量超过0.3 erg cm-2。在这里，我们报告检测到一个衰落的无线电对应这一事件。我们开始了一个从0.2到250千兆赫的监测方案，并获得了一个高分辨率的21厘米无线电频谱，可以追踪星际中性氢云。光谱分析产生了SGR 1806 - 20的第一个直接距离测量：源位于大于6.4 kpc的距离，我们认为它比9.8 kpc更近。如果是正确的，我们的距离估计降低了爆炸的总能量，并放松了对理论模型的要求。射电源的能量和快速衰变与通常用于γ射线爆发的余辉模型不相容。相反，我们认为快速衰减的无线电发射来自爆炸过程中喷出的碎片。
It was established over a decade ago that the remarkable high-energy transients known as soft γ-ray repeaters (SGRs) are located in our Galaxy,and originate from neutron stars with intense (≤ 1015G) magnetic fields—so-called ‘magnetars’. On 27 December 2004, a giant flare with a fluence exceeding 0.3 erg cm-2was detected from SGR 1806–20. Here we report the detection of a fading radio counterpart to this event. We began a monitoring programme from 0.2 to 250 GHz and obtained a high-resolution 21-cm radio spectrum that traces the intervening interstellar neutral hydrogen clouds. Analysis of the spectrum yields the first direct distance measurement of SGR 1806 - 20: the source is located at a distance greater than 6.4 kpc and we argue that it is nearer than 9.8 kpc. If correct, our distance estimate lowers the total energy of the explosion and relaxes the demands on theoretical models. The energetics and the rapid decay of the radio source are not compatible with the afterglow model that is usually invoked for γ-ray bursts. Instead, we suggest that the rapidly decaying radio emission arises from the debris ejected during the explosion.