伽玛射线暴喷流数值模拟及相关辐射过程研究

The study of gamma-ray bursts (GRBs) is one of the most active fields in astrophysics. In the past ten years, the Swift and Fermi satellites have brought to us fruitful observational data, leading to the discovery of some new phenomena. However, many crucial problems of GRBs remain to be answered, among which the production and the propagation of the jet and the physical origin of the prompt emission are very significant. The applicant has been engaged in the study of high energy astrophysics for more than 8 years. He has published 26 SCI papers, which were cited by other authors by more than 230 times. Based on our researches on the jet simulation and the prompt emission (published on ApJS/ApJ), we will establish a comprehensive numerical scheme that calculates the processes including the launching of the relativistic jet all the way to the emission of the GRB. At the same time, our works would help to answer some opening questions, such as the composition of the jet, the magnetic field strength, the particle acceleration mechanism, and the radiation mechanism of the emitting region. Both POLAR and HXTM are now collecting the GRB data, which offers a great opportunity for us to operate our studies smoothly. It is expected that our research will provide helpful clues to the nature of the GRBs.

伽玛射线暴（简称伽玛暴）是当前天体物理中最活跃的研究领域之一。过去十年，Swift、Fermi卫星提供了丰富的伽玛暴观测资料，让我们认识了很多伽玛暴的新现象。然而，伽玛暴的很多基本问题依然亟待解决，伽玛暴喷流如何产生、传播、辐射就是其中的重点。申请人长期从事高能天体物理研究，已正式发表SCI论文26篇，论文被他引230余篇次。以我们近期关于喷流数值模拟、瞬时辐射计算的工作（发表于ApJS/ApJ）为基础，我们将建立一套从喷流喷出，到伽玛射线辐射产生的完整计算方案，尝试揭示出伽玛暴喷流的物质组成成分、辐射区磁场强度、粒子加速机制、辐射机制等基本问题的答案。我国的POLAR、慧眼-HXMT望远镜已经在积累伽玛暴观测数据，为我们研究的顺利开展提供了极大的机遇。预计我们的研究将对揭示伽玛暴的本质有重要的推动。

随着我国的慧眼-HXMT、POLAR、GECAM卫星投入运行，以及未来EP、SVOM卫星的发射，伽玛射线暴已经进入攻克关键科学问题的研究阶段。本项目围绕伽玛暴瞬时辐射，以磁流体数值模拟、数值计算为主要研究手段，研究伽玛暴相对论喷流的动力学和辐射物理规律，从而推动伽玛暴这一前沿领域的研究进展。本项目在天文学领域国际高水平期刊上发表研究论文15篇，取得以下重要结果：（1）分别在同步辐射模型框架（Gao et al., 2021, A&A）和光球辐射模型框架（Meng et al., 2022, MNRAS）下解释了伽玛暴谱峰值能量演化模式和谱指数的统计分布性质，论证了伽玛暴能谱中逆康普顿散射成分在观测中呈现的必要条件是喷流的整体洛伦兹因子大于1000（Zhang et al., 2019, ApJ）。（2）基于磁流体数值模拟，揭示了双中子星并合引力波暴GRB 170817A喷流传播过程中形成的喷流-茧物质角分布和辐射能谱性质（Geng et al. 2019, ApJL）。（3）提出重复快速射电暴起源新模型，解释了重复FRB 180916的周期性活动现象，并为检验奇异夸克物质假说提供一种新途径（Geng et al., 2021, The Innovation）。基于中子星与小行星碰撞模型成功解释了来自银河系内磁陀星SGR 1935+2154的低光度快速射电暴FRB 200428和X射线爆发成协现象（Geng et al., 2020, ApJL）。