短伽玛暴的射电辐射与能源机制

This project is focused on the studies of radio emission and energy mechanism for short GRBs (SGRBs). Firstly, using Bayesian block method, we will reanalyze and select SGRBs, SGRBs with extended emission (SGRBEE) and long GRBs with extended emission (LGRBEE) as our main objects of study, and estimate the contribution of host galaxy to their radio afterglows by a newly found method of flux ratio between host and source. Secondly, based on observational features of the three kinds of bursts, their numerical radio afterglow light curves and energy continuum will be given to cover the full frequency bands of FAST and detectability is also to be tested for Five-hundred-meter Aperture Spherical radio Telescope (FAST) together with SKA, LOFAR and VLA. Finally, luminosity functions of the above three types of bursts will be constructed in order to investigate their individually stellar formation history, local occurrence rate as well as detection possibility. For one of SGRBs and SGRBEEs, a case study is essential and to be done for the sake of understanding their inner physical structure, radio properties and circum-burst enviroment. Furthermore, investigations in the project will help us to learn the origin of radio radiations and progenitors of SGRBs and EE components. In addition, this project is quite valuable for making observation plan of radio transients especially the radio afterglows. It is hopefully to bring up the local astronomical talents in radio astronomy field.

本项目详细研究短伽玛暴的射电辐射性质和能源模型。利用贝叶斯分块方法从BATSE、Swift暴中筛选短暴（SGRB）、延伸辐射型短暴（SGRBEE）和延伸辐射型长暴（LGRBEE）为主要研究对象，运用我们最近发现的射电流量比方法估计宿主星系对暗弱射电余辉的贡献。根据这三类暴的观测性质，采用数值计算方法在理论上给出它们涵盖FAST观测频段的射电余辉曲线和宽波段谱，探讨FAST探测短暴射电余辉的可能性。为了检验和对比SGRB、SGRBEE和LGRBEE的能源机制，我们构建三类暴的光度函数来讨论它们各自与恒星形成率的关系、当地发生率以及探测率；对射电数据较丰富的SGRB和SGRBEE进行详细的个体研究，期待从多波段深入揭示其内部物理结构、射电辐射性质和暴周环境的特点。该项目对于理解短伽玛暴和延伸辐射暴的能源本质具有重要科学价值，对FAST对河外暂现射电源尤其伽玛暴射电余辉观测方案制定提供科学依据。

本项目利用贝叶斯分块方法从BATSE、Swift暴中筛选短暴（SGRB）、延伸辐射型短暴（SGRBEE）和延伸辐射型长暴（LGRBEE）为主要研究对象，运用射电流量比方法估计宿主星系对暗弱射电余辉的贡献。根据这三类暴的观测性质，采用数值计算方法在理论上给出它们涵盖FAST观测频段的射电余辉曲线和宽波段谱，探讨FAST、LOFAR以及SKA等探测伽玛暴尤其是短暴射电余辉的可能性。特别地，我们重新利用Swift和Fermi伽玛暴样本构建新的能谱关系，发现短暴能谱关系的幂率指数与长暴基本一致，为两类伽玛暴存在相同的辐射机制提供了重要依据。同时，我们详细探讨了两个特殊短伽玛暴，即GRB170817A和GRB090510（延伸辐射短暴），发现前者与短暴的经验能谱关系严重不符，而后者符合峰值能量-各向同性能量、峰值能量-峰值光度关系，但背离峰值能量-喷流校正能量关系。最新研究表明，GRB170817A和GRB090510分别起源于双中子星并合和黑洞双星并合过程，我们的研究结果与此结论是吻合的。该项目对于理解短伽玛暴和延伸辐射暴的能源本质具有重要科学价值，对FAST对河外暂现射电源尤其伽玛暴射电余辉观测方案制定提供科学依据。