QUASI-PERIODIC OSCILLATIONS IN SHORT RECURRING BURSTS OF THE SOFT GAMMA REPEATER J1550−5418
QUASI-PERIODIC OSCILLATIONS IN SHORT RECURRING BURSTS OF THE SOFT GAMMA REPEATER J1550−5418
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软伽马中继器 J1550−5418 短循环突发中的准周期振荡
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发表时间：
2014
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影响因子：
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通讯作者：
G. Younes
中科院分区：
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作者：
D. Huppenkothen;C. D’Angelo;A. Watts;L. Heil;M. Klis;A. J. Horst;C. Kouveliotou;M. Baring;E. Gogus;J. Granot;Y. Kaneko;Lin Lin;A. Kienlin;G. Younes
磁星巨星耀斑中准周期振荡的发现为中子星星星震学的研究开辟了新的前景。巨大的耀斑的稀缺性使得寻找QPO在较短的，从软伽玛中继站（SGRs）的期望的众多爆发。在Huppenkothen等人的著作中，我们发展了一种在短磁星爆发中寻找QPO的贝叶斯方法，考虑了复杂爆发结构的影响，并在小样本的爆发上证明了它的可行性。在这里，我们将同样的方法应用于SGR J1550−5418的286个爆发风暴的更大样本。我们报告了一个候选信号在260 Hz的搜索的个人爆发，这是相当广泛的。当对单个触发器中的多个爆发的周期图进行平均时，我们还发现了两个频率为0.93 Hz的QPO和一个频率为127 Hz的QPO，其频率接近之前在磁星巨耀斑中观察到的QPO。最后，第一次，我们探索的整体突发变化的样本和报告的幂律指数的宽带模型表征非周期性突发变化和突发持续时间之间的弱反相关性：较短的突发有陡峭的幂律指数比较长的突发。这表明，较长的爆发在较宽的时间尺度范围内变化，而不仅仅是短爆发的较长版本。
The discovery of quasi-periodic oscillations (QPOs) in magnetar giant flares has opened up prospects for neutron star asteroseismology. The scarcity of giant flares makes a search for QPOs in the shorter, far more numerous bursts from soft gamma repeaters (SGRs) desirable. In Huppenkothen et al., we developed a Bayesian method for searching for QPOs in short magnetar bursts, taking into account the effects of the complicated burst structure, and have shown its feasibility on a small sample of bursts. Here we apply the same method to a much larger sample from a burst storm of 286 bursts from SGR J1550−5418. We report a candidate signal at 260 Hz in a search of the individual bursts, which is fairly broad. We also find two QPOs at ∼93 Hz, and one at 127 Hz, when averaging periodograms from a number of bursts in individual triggers, at frequencies close to QPOs previously observed in magnetar giant flares. Finally, for the first time, we explore the overall burst variability in the sample and report a weak anti-correlation between the power-law index of the broadband model characterizing aperiodic burst variability and the burst duration: shorter bursts have steeper power-law indices than longer bursts. This indicates that longer bursts vary over a broader range of timescales and are not simply longer versions of the short bursts.