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arXiv 2202.12460astro-ph.HE
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GRB 200826 A:一个主辐射缺失的长GRB的前兆

GRB 200826A: A Precursor of a Long GRB with Missing Main Emission

Xiangyu Ivy Wang, Bin-Bin Zhang, Wei-Hua Lei

摘要:

最近发现的奇特的伽马射线暴GRB 200826 A给Bracksar模型带来了一个难题。尽管突发的所有其他特征与其为II型一致(即,大质量恒星的坍缩)事件,观测到的事件持续时间仅约为1秒,这与预测的双星事件允许的时间尺度范围不一致。为了解决这一难题,这封{ \it Letter}提出,原始爆发可能是一个由前兆和主发射(ME)相组成的固有长GRB。然而,由于喷流的进动或伴星的阻挡,主发射阶段被错过了,只留下了短持续时间的GRB 200826 A。有趣的是,我们发现GRB 200826 A的时间和光谱特性与GRB 160625 B中观察到的明亮前体非常相似。此外,假设GRB 200826 A的原型爆发与GRB 160625 B的原型爆发相似,我们发现观测者可能确实错过了它的主要发射,这是因为喷流进动或伴随障碍模型引起的几何效应。我们的方法提供了一个自然的解释GRB 200826 A类爆发,并同意这些事件的罕见性。

英文摘要:

The recently discovered peculiar gamma-ray burst GRB 200826A poses a dilemma for the collapsar model. Although all other characteristics of the burst are consistent with it being a Type II (i.e., collapse of a massive star) event, the observed duration of the event is only approximately 1 s, which is at odds with the predicted allowable timescale range for a collapsar event. To resolve this dilemma, this {\it Letter} proposes that the original burst could be an intrinsically long GRB comprising of a precursor and a main emission (ME) phase. However, the main emission phase is missed due to either precession of the jet or the obstruction of a companion star, leaving only the precursor observed as a short-duration GRB 200826A. Interestingly, we found that the temporal and spectral properties of GRB 200826A broadly resembled those of the bright precursor observed in GRB 160625B. Furthermore, assuming the prototype burst of GRB 200826A is similar to that of GRB 160625B, we found that the observer may indeed miss its main emission because of geometric effects caused either by jet precession or companion-obstruction models. Our approach provides a natural explanation for the GRB 200826A-like bursts and agrees with the rarity of those events.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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