Repeating Emission Episodes in Gamma-Ray Bursts: Millilensing or Jet Precession?
Repeating Emission Episodes in Gamma-Ray Bursts: Millilensing or Jet Precession?
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DOI：
10.3847/1538-4357/acba0d
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发表时间：
2023-03
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影响因子：
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通讯作者：
He Gao;An-Hua Li;W. Lei;Zhi-Qiang You
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作者：
He Gao;An-Hua Li;W. Lei;Zhi-Qiang You
近年来，一些光变曲线由具有相似时间剖面的重复发射事件组成的伽玛暴引起了人们的广泛关注。他们被认为是millilensing事件的候选者，尽管缺乏确凿的证据，因为没有红移测量，也没有任何这些候选者的角偏移检测。在这里，我们表明，没有调用引力透镜，这些伽玛暴的重复光变曲线特性也可以解释下的喷流进动模型，只要在每个进动周期的可检测周期小于进动周期，和进动周期接近喷流发射持续时间。通过拟合这些伽玛暴的伽玛射线光变曲线，我们认为这些暴的喷流进动角应该相对较小（例如，θ p < 5.°3），这些爆发的喷流结构更可能是高斯型的。这一结果提示我们在识别毫米波伽玛暴时要小心。多波段余辉数据，特别是角偏移检测是必不可少的，提供全面的理由，这种识别。
Recently, some gamma-ray bursts (GRBs) whose light curves consist of repeating emission episodes with similar temporal profiles have attracted extensive attention. They are proposed to be candidates of millilensing events, although smoking gun evidence is lacking, since there are no redshift measurements and no angular offset detections for any of these candidates. Here we show that without invoking gravitational lensing, the repeating light-curve properties of these GRBs could also be interpreted under the jet precession model, as long as the detectable period in every precession circle is less than the precession period, and the precession period is close to the jet emission duration. By fitting the gamma-ray light curves of these GRBs, we suggest that the jet precession angle for these bursts should be relatively small (e.g., θ p < 5.°3), and the jet structure for these bursts are more likely Gaussian. The results suggest us to be careful when identifying millilensing GRBs. Multiband afterglow data and especially angular offset detections are essential to provide comprehensive justification for this identification.