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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2511.18371 |
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| _version_ | 1866917099941658624 |
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| author | Tan, Wen-Jun Wang, Chen-Wei Xiong, Shao-Lin Zheng, Shi-Jie He, Jiang Zhao, Xiao-Yun Huang, Yue Yi, Shu-Xu Li, Bing Gao, He Wu, Bo-bing Zhang, Bing Daigne, Frederic Bernardini, Maria-Grazia Zhang, Bin-Bin Basa, Stephane Cordier, Bertrand Deng, Jin-Song Dong, Yong-Wei Dornic, Damien Godet, Olivier Han, Xu-Hui Huang, Mao-Hai Lachaud, Cyril Li, Hua-Li Maggi, Pierre Piron, Frederic Qiu, Yu-Lei Schanne, Stephane Song, Li-Ming Turpin, Damien Vergani, Susanna Wang, Jing Wang, Ping Wei, Jian-Yan Wu, Chao Xin, Li-Ping Xu, Yang Zhang, Li Zhang, Shuang-Nan |
| author_facet | Tan, Wen-Jun Wang, Chen-Wei Xiong, Shao-Lin Zheng, Shi-Jie He, Jiang Zhao, Xiao-Yun Huang, Yue Yi, Shu-Xu Li, Bing Gao, He Wu, Bo-bing Zhang, Bing Daigne, Frederic Bernardini, Maria-Grazia Zhang, Bin-Bin Basa, Stephane Cordier, Bertrand Deng, Jin-Song Dong, Yong-Wei Dornic, Damien Godet, Olivier Han, Xu-Hui Huang, Mao-Hai Lachaud, Cyril Li, Hua-Li Maggi, Pierre Piron, Frederic Qiu, Yu-Lei Schanne, Stephane Song, Li-Ming Turpin, Damien Vergani, Susanna Wang, Jing Wang, Ping Wei, Jian-Yan Wu, Chao Xin, Li-Ping Xu, Yang Zhang, Li Zhang, Shuang-Nan |
| contents | The Space-based multiband astronomical Variable Objects Monitor (SVOM), detected its first short gamma-ray burst, GRB 240715A, in-flight, which was jointly observed by Fermi. Based on observational data of SVOM/GRM and Fermi/GBM, we perform a comprehensive temporal and spectral analysis for individual pulse in the prompt emission of this burst, and novel characteristics are revealed. Firstly, opposite evolutions of spectral lag are found in the first and third pulse of this burst. Second, the large negative lag of the first pulse is an outlier in short GRB sample, especially when the pulse duration is considered. Spectral analysis shows that the negative lag of the first pulse is caused by the evolution of spectrum index, and is irrelevant to Epeak, which is inconsistent with the previous study. The intrinsic mechanism is probably attributed to electron cooling in the decaying magnetic field, which leads to the continuous hardening of the spectrum index and results in negative lag. Furthermore, spectral analysis also shows that the third pulse is more likely to be described by a quasi-thermal spectrum, indicating the existence of photospheric emission. It is difficult to explain how the synchrotron radiation appears before photospheric emission in a single GRB and some assumptions are discussed. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_18371 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | GRB 240715A: Revealing Novel Intrinsic Mechanism by Different Individual Pulse Tan, Wen-Jun Wang, Chen-Wei Xiong, Shao-Lin Zheng, Shi-Jie He, Jiang Zhao, Xiao-Yun Huang, Yue Yi, Shu-Xu Li, Bing Gao, He Wu, Bo-bing Zhang, Bing Daigne, Frederic Bernardini, Maria-Grazia Zhang, Bin-Bin Basa, Stephane Cordier, Bertrand Deng, Jin-Song Dong, Yong-Wei Dornic, Damien Godet, Olivier Han, Xu-Hui Huang, Mao-Hai Lachaud, Cyril Li, Hua-Li Maggi, Pierre Piron, Frederic Qiu, Yu-Lei Schanne, Stephane Song, Li-Ming Turpin, Damien Vergani, Susanna Wang, Jing Wang, Ping Wei, Jian-Yan Wu, Chao Xin, Li-Ping Xu, Yang Zhang, Li Zhang, Shuang-Nan High Energy Astrophysical Phenomena The Space-based multiband astronomical Variable Objects Monitor (SVOM), detected its first short gamma-ray burst, GRB 240715A, in-flight, which was jointly observed by Fermi. Based on observational data of SVOM/GRM and Fermi/GBM, we perform a comprehensive temporal and spectral analysis for individual pulse in the prompt emission of this burst, and novel characteristics are revealed. Firstly, opposite evolutions of spectral lag are found in the first and third pulse of this burst. Second, the large negative lag of the first pulse is an outlier in short GRB sample, especially when the pulse duration is considered. Spectral analysis shows that the negative lag of the first pulse is caused by the evolution of spectrum index, and is irrelevant to Epeak, which is inconsistent with the previous study. The intrinsic mechanism is probably attributed to electron cooling in the decaying magnetic field, which leads to the continuous hardening of the spectrum index and results in negative lag. Furthermore, spectral analysis also shows that the third pulse is more likely to be described by a quasi-thermal spectrum, indicating the existence of photospheric emission. It is difficult to explain how the synchrotron radiation appears before photospheric emission in a single GRB and some assumptions are discussed. |
| title | GRB 240715A: Revealing Novel Intrinsic Mechanism by Different Individual Pulse |
| topic | High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2511.18371 |