论文标题
GRB 200826a：长GRB的前体，缺少主排放
GRB 200826A: A Precursor of a Long GRB with Missing Main Emission
论文作者
论文摘要
最近发现的奇特伽马射线爆发GRB 200826a为Collapsar模型带来了困境。尽管爆发的所有其他特征都与它是II型（即大量恒星的崩溃）事件一致，但事件的持续时间仅为1 s，与预测的折叠事件预测的可允许的时间表范围相反。为了解决这一难题，此{\ it Letter}提出原始爆发可能是由前体和主要发射（ME）阶段组成的本质上长的GRB。但是，由于射流的进攻或伴侣恒星的阻塞，主要的发射阶段被遗漏，仅将前体视为短期GRB 200826a。有趣的是，我们发现GRB 200826a的时间和光谱特性与GRB 160625b中观察到的明亮前体的特性广泛相似。此外，假设GRB 200826a的原型爆发与GRB 160625B相似，我们发现观察者确实可能会因为由喷气疗法或伴随式攻击模型引起的几何效应而错过其主要发射。我们的方法为GRB 200826a般的爆发提供了自然的解释，并同意这些事件的稀有性。
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.
