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arXiv 2602.05404astro-ph.HE
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长持续GRB 110801A的双爆发性质及其早期余辉演化

The Double-Burst Nature and Early Afterglow Evolution of Long GRB 110801A

Purple Mountain Observatory, Chinese Academy of Sciences(中国科学院紫金山天文台);School of Astronomy and Space Science, University of Science and Technology of China(中国科学技术大学天文与空间科学学院)

Qiu-Li Wang, Hao Zhou, Yun Wang, Jia Ren, Zhi-Ping Jin, Da-Ming Wei

AI总结:

GRB 110801A的双爆发性质及其早期余辉演化通过多波段观测揭示,双组分模型解释了不同能量区的发射来源。

摘要:

我们利用尼尔·乔治尔斯斯威夫特天文台和地面望远镜的多波段数据,对持续时间长的伽马射线暴GRB 110801A进行了全面的时间和光谱分析。γ射线发射显示出明显的双事件("双爆发")结构。快速的光学和X射线观测提供了对第二爆发的完整覆盖。光学光变曲线在触发后约135秒开始上升,显著早于在X射线和γ射线中观测到的第二发射事件约320秒。这种色散行为表明光学和高能发射有不同的物理起源。在第二事件期间联合宽波段光谱拟合(从光学到γ射线)发现,由幂律加带函数组成的双组分模型比单组分模型拟合更优。我们将幂律组分解释为第一爆发的余辉(主导光学波段),而带组分归因于第二爆发的即时发射(主导高能波段)。还发现物理上同步加速模型也是解释高能发射的可行候选者。关于余辉,早期光学光变曲线显示出从约t^{2.5}的上升到约t^{6.5}的急剧转变,这可以通过涉及反冲激波(RS)和前向激波(FS)组分的场景很好地解释。我们限制了爆发的关键物理参数,得出初始洛伦兹因子Γ_0≈60,喷流半张角θ_j≈0.09,以及等效动能E_{k,iso}≈10^{54.8} erg。

英文摘要:

We present a comprehensive temporal and spectral analysis of the long-duration gamma-ray burst GRB 110801A, utilizing multi-band data from the Neil Gehrels Swift Observatory and ground-based telescopes. The $γ$-ray emission exhibits a distinct two-episode (``double-burst'') structure. Rapid follow-up observations in the optical and X-ray bands provide full coverage of the second burst. The optical light curve begins to rise approximately 135 s after the trigger, significantly preceding the second emission episode observed in X-rays and $γ$-rays at $\sim 320$ s. This chromatic behavior suggests different physical origins for the optical and high-energy emissions. Joint broadband spectral fitting (optical to $γ$-rays) during the second episode reveals that a two-component model, consisting of a power-law plus a Band function, provides a superior fit compared to single-component models. We interpret the power-law component as the afterglow of the first burst (dominating the optical band), while the Band component is attributed to the prompt emission of the second burst (dominating the high-energy bands). A physical synchrotron model is also found to be a viable candidate to explain the high-energy emission. Regarding the afterglow, the early optical light curve displays a sharp transition from a rise of $\sim t^{2.5}$ to $\sim t^{6.5}$, which is well-explained by a scenario involving both reverse shock (RS) and forward shock (FS) components. We constrain the key physical parameters of the burst, deriving an initial Lorentz factor $Γ_0 \sim 60$, a jet half-opening angle $θ_j \sim 0.09$, and an isotropic kinetic energy $E_{\rm k,iso} \sim 10^{54.8}$ erg.

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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