GRB 240825A：早期逆冲击及其物理意义
高能天体物理现象
2025-08-12 v2
摘要
早期的多波段观测提供了关于负责Gamma射线暴(GRB)及其与周围介质相互作用的相对论性喷流本质的关键见解。我们展示了来自GRB 240825A的数据，涵盖17个太空-和地面基站/仪器，覆盖NIR/光学至X射线和GeV波段，spanning从prompt辐射到afterglow阶段，由Swift和Fermi触发。早期afterglow观测由SVOM/C-GFT完成，光谱观测由GTC、VLT和TNG进行，后来确定了该暴的红移(z = 0.659)。对Swift-BAT和Fermi-GBM/LAT观测到的prompt辐射光谱的综合分析揭示了一个罕见且显著的高能截止，约为76 MeV。假设该截止是由于γγ吸收导致的，我们将对初始洛伦兹因子的上限置于Γ0 < 245。光学/NIR和GeV afterglow光度曲线可由标准外部冲击模型描述，早期发射主导由逆冲击(RS)主导，随后转向正冲击(FS)发射。我们的afterglow建模给出了一致的初始洛伦兹因子估计(Γ0 ≈ 234)。此外，RS到FS的磁场比率(RB ≈ 302)表明，逆冲击区域的磁化程度显著高于FS区域。推导出等效各向同性动能Ekin,iso = 5.25 × 10^54 erg，并估计相应的γ射线辐射效率为ηγ = 3.1%。另一方面，标准afterglow模型无法再现GRB 240825A的X射线光度曲线，呼吁改进模型来表征所有多波段数据。
引用
@article{arxiv.2507.02806,
title = {GRB 240825A: Early Reverse Shock and Its Physical Implications},
author = {Chao Wu and Yun Wang and Hua-Li Li and Li-Ping Xin and Dong Xu and Benjamin Schneider and Antonio de Ugarte Postigo and Gavin Lamb and Andrea Reguitti and Andrea Saccardi and Xing Gao and Xing-Ling Li and Qiu-Li Wang and Bing Zhang and Jian-Yan Wei and Shuang-Nan Zhang and Frédéric Daigne and Jean-Luc Atteia and Maria-Grazia Bernardini and Hong-bo Cai and Arnaud Claret and Bertrand Cordier and Jin-Song Deng and Olivier Godet and Diego Götz and Xu-Hui Han and Zhe Kang and Guang-Wei Li and Zhen-Wei Li and Cheng-Zhi Liu and Xiao-Meng Lu and You Lv and Julian P Osborne and Jesse Palmerio and Yu-Lei Qiu and Stéphane Schanne and Damien Turpin and Susanna Diana Vergani and Jing Wang and Yu-Jie Xiao and Wen-Jin Xie and Yang Xu and Zhu-Heng Yao and Pin-Pin Zhang and Ruo-Son Zhang and Cheng-Wei Zhu and Riccardo Brivio and Stefano Covino and Paolo D'Avanzo and Matteo Ferro and Andrea Melandri and Andrea Rossi and José Feliciano Agüí Fernández and Christina C. Thöne and Chun-Hai Bai and Ali Esamdin and Abdusamatjan Iskandar and Shahidin Yaqup and Yu Zhang and Tu-Hong Zhong and Shao-Yu Fu and Shuai-Qing Jiang and Xing Liu and Jie An and Zi-Pei Zhu and Jia-Xin Cao and En-Wei Liang and Da-Bin Lin and Xiang-Gao Wang and Guo-Wang Du and Xin-Zhong Er and Yuan Fang and Xiao-Wei Liu and Christophe Adami and Michel Dennefeld and Emeric Le Floc'h and Johan Peter Uldall Fynbo and Páll Jakobsson and Daniele Bjørn Malesani and Zhi-Ping Jin and Jia Ren and Hao Wang and Da-Ming Wei and Hao Zhou and Sergio Campana and Shiho Kobayashi and Massimiliano De Pasquale},
journal= {arXiv preprint arXiv:2507.02806},
year = {2025}
}
备注
31 pages, 9 Figures, 10 Tables