Photometric and Spectroscopic Observations of GRB 190106A: Emission from Reverse and Forward Shocks with Late-time Energy Injection
Photometric and Spectroscopic Observations of GRB 190106A: Emission from Reverse and Forward Shocks with Late-time Energy Injection
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DOI：
10.3847/1538-4357/acbd96
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发表时间：
2023-02
期刊：
影响因子：
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通讯作者：
Zi-pei Zhu;Dong Xu;J. Fynbo;Shao-Yu Fu;Xing Liu;Shuai-Qing Jiang;S. Xiao;Wei Xie;Y. Zou-Y.-Z
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文献类型：
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作者：
Zi-pei Zhu;Dong Xu;J. Fynbo;Shao-Yu Fu;Xing Liu;Shuai-Qing Jiang;S. Xiao;Wei Xie;Y. Zou-Y.-Z
对伽玛射线暴的早期光学观测对研究其中心引擎及其物理过程具有重要意义。然而，在迄今为止观测到的数千颗恒星中，只有少数几颗在瞬间发射开始后的最初几分钟内拥有可见光波长的数据。在这里，我们报道了GRB 190106A，在Swift/BAT触发后仅36秒，即在提示发射阶段，在光学波段观测到其余辉。早期光学余辉呈现双峰结构，随后是正常衰减，在~ t0 + 1天后衰减更快。我们提出了GRB 190106A的光学光度和光谱观测。利用星龙2.16 m/BFOSC光谱观测得到了金属吸收谱线的红移。从BFOSC光谱中，我们测量到z = 1.861±0.002。双峰光曲线是逆正外激波模型预测的一个重要特征。在x射线和光学曲线中，浅衰减之后是正常衰减，用标准的带后期能量注入的前冲模型可以很好地解释。因此，GRB 190106A提供了一个研究反向和正向冲击下GRB发射的案例。
Early optical observations of gamma-ray bursts can significantly contribute to the study of the central engine and physical processes therein. However, of the thousands observed so far, only a few have data at optical wavelengths in the first minutes after the onset of the prompt emission. Here we report on GRB 190106A, whose afterglow was observed in optical bands just 36 s after the Swift/BAT trigger, i.e., during the prompt emission phase. The early optical afterglow exhibits a bimodal structure followed by a normal decay, with a faster decay after ∼T 0 + 1 day. We present optical photometric and spectroscopic observations of GRB 190106A. We derive the redshift via metal absorption lines from Xinglong 2.16 m/BFOSC spectroscopic observations. From the BFOSC spectrum, we measure z = 1.861 ± 0.002. The double-peak optical light curve is a significant feature predicted by the reverse-forward external-shock model. The shallow decay followed by a normal decay in both the X-ray and optical light curves is well explained with the standard forward-shock model with late-time energy injection. Therefore, GRB 190106A offers a case study for GRB emission from both reverse and forward shocks.