发表机构
University of Maryland, Baltimore County; NASA Goddard Space Flight Center; University of Maryland, College Park; University of Tampa; The Pennsylvania State University（马里兰大学巴尔的摩分校; 美国国家航空航天局戈达德太空飞行中心; 马里兰大学帕克分校; 坦帕大学; 宾夕法尼亚州立大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究分析GRB 241030A，发现其X射线和伽马射线中存在约0.04和0.08 Hz的准周期振荡，贝叶斯因子超10^200，最可能源于喷流穿过双星作用产生的规则壳层。
AI 中文摘要
已有少数伽马射线暴在伽马射线强度中报告了准周期振荡（QPO）。这些QPO可能与源中的基本频率相关，这将为理解这些系统提供新的见解。在此，我们报告了对GRB 241030A的分析，这是一个持续数分钟的爆发，包含约10个伽马射线耀发，其近似周期性约为f~0.04 Hz和f~0.08 Hz。这种准周期性在Swift X射线望远镜（XRT）的X射线数据以及Swift爆发警报望远镜（BAT）和费米伽马射线暴监测器（GBM）的伽马射线数据中均可观测到。与仅包含红噪声的功率谱模型相比，支持洛伦兹型QPO的贝叶斯因子超过10^200，即使红噪声由多达四个不同斜率的片段描述时也是如此。然而，将该功率谱特征解释为QPO而非红噪声中的波动，因该特征频率较低以及计数数量极大而变得复杂，后者放大了与平滑功率谱分布的差异。在讨论了表观QPO的性质后，我们探讨了几种可能在该频率调制通量的过程。在所考虑的机制中，我们发现最合理的解释是GRB喷流穿过环绕爆发介质的规则间隔壳层，这些壳层可能由偏心前身星系统中近星点附近的双星相互作用产生。
英文摘要
Quasiperiodic oscillations (QPOs) in gamma-ray intensity have been reported from a few gamma-ray bursts. These QPOs could be related to fundamental frequencies in the sources, which would lead to new insights about these systems. Here we report on our analysis of GRB~241030A, a several-minute-long burst with $\sim 10$ gamma-ray flares that have approximate periodicities at f ~ 0.04 Hz and f ~ 0.08 Hz. This quasi-periodicity is seen in X-rays with the Swift X-Ray Telescope (XRT) as well as in gamma-rays with the Swift Burst Alert Telescope (BAT) and the Fermi Gamma-ray Burst Monitor (GBM). Compared with a power spectral model that has only red noise, the Bayes factor in favor of a Lorentzian-shaped QPO is more than $10^{200}$, even when the red noise is described by segments with up to four different slopes. However, the interpretation of this power spectral feature as a QPO rather than as a fluctuation in red noise is complicated by the low frequency of the feature as well as the extremely large number of counts, which amplifies differences from smooth power spectral distributions. After discussing the properties of the apparent QPO, we discuss a few processes that could plausibly modulate the flux at this frequency. Among the mechanisms considered, we find the most plausible explanation to be a GRB jet passing through regularly spaced shells of circumburst material, possibly produced by binary interactions near periastron in an eccentric progenitor system.
Comments18 pages, 13 figures, submitted to ApJ
