Evidence of Minijet Emission in a Large Emission Zone from a Magnetically Dominated Gamma-Ray Burst Jet
Shu-Xu Yi, Chen-Wei Wang, Xu Shao, R. Moradi, H. Gao, Bing Zhang, S. L. Xiong, Shuang‐Nan Zhang, Wenjun Tan, Jiacheng Liu, W. C. Xue, Chao Zheng, Chao Zheng, Y. Wang, Peng Zhang, Zhenghua An, Ce Cai, Pei-Yi Feng, K. Gong, Da-Feng Guo, Yang Huang, Bing Li, Xiao‐Bo Li, Xinqiao Li, X.-J. Liu, Yueqiang Liu, Xiang Ma, W.-X. Peng, Rui Qiao, L. M. Song, J. Wang, Ping Wang, Y. Wang, Xuanye Wen, Shuo Xiao, Ying Xu, S. B. Yang, Qi-Bing Yi, Deliang Zhang, F. Zhang, Hongmei Zhang, Jing‐Ping Zhang, Zhen Zhang, X. Y. Zhao, Y. Zhao, Shijie Zheng
Abstract
Abstract The second brightest gamma-ray burst (GRB) in history, GRB 230307A, provides an ideal laboratory to study the mechanism of GRB prompt emission thanks to its extraordinarily high photon statistics and its single-episode activity. Here we demonstrate that the rapidly variable components of its prompt emission compose an overall broad single pulse-like profile. Although these individual rapid components are aligned in time across all energy bands, this overall profile conspires to show a well-defined energy-dependent behavior that is typically seen in single GRB pulses. Such a feature demonstrates that the prompt emission of this burst is from many individual emitting units that are casually linked in a emission site at a large distance from the central engine. Such a scenario is in natural consistency with the internal-collision-induced magnetic reconnection and turbulence framework, which invokes many minijets due to local magnetic reconnection that constantly appear and disappear in a global magnetically dominated jet.