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arXiv 1908.10885astro-ph.HE
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来自GRB 160821 A的时变极化γ射线:有序磁场的证据

Time varying polarized gamma-rays from GRB 160821A: evidence for ordered magnetic fields

Vidushi Sharma, Shabnam Iyyani, Dipankar Bhattacharya, Tanmoy Chattopadhyay, A. R. Rao, E. Aarthy, Santosh V. Vadawale, N. P. S. Mithun, Varun. B. Bhalerao, Felix Ryde, Asaf Peer

摘要:

GRB 160821 A是{ \it Fermi}伽马射线太空望远镜观测到的第三大能量伽马射线爆发。基于{ \it AstroSat}上的碲锌镉成像仪(CZTI)的观测结果,本文报告了迄今为止最确凿的证据:(i)高线性偏振($66^{+26}_{-27} \%$ ; $5.3 σ$探测);(ii)偏振角随时间的变化,分别在$3.5 σ$和$3.1 σ$探测的爆发上升和衰减阶段发生两次。报告了两个感兴趣参数的所有置信水平。这些观测结果强烈表明同步辐射产生的磁场线是高度有序的角度尺度上的$1/Γ$,其中$Γ$是洛伦兹因子的流出。

英文摘要:

GRB 160821A is the third most energetic gamma ray burst observed by the {\it Fermi} gamma-ray space telescope. Based on the observations made by Cadmium Zinc Telluride Imager (CZTI) on board {\it AstroSat}, here we report the most conclusive evidence to date of (i) high linear polarization ($66^{+26}_{-27} \%$; $5.3 σ$ detection), and (ii) variation of its polarization angle with time happening twice during the rise and decay phase of the burst at $3.5 σ$ and $3.1 σ$ detections respectively. All confidence levels are reported for two parameters of interest. These observations strongly suggest synchrotron radiation produced in magnetic field lines which are highly ordered on angular scales of $1/Γ$, where $Γ$ is the Lorentz factor of the outflow.

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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