Triggering the Untriggered: The First Einstein Probe-detected Gamma-Ray Burst 240219A and Its Implications
| Autor: | Yi-Han Iris Yin, Bin-Bin Zhang, Jun Yang, Hui Sun, Chen Zhang, Yi-Xuan Shao, You-Dong Hu, Zi-Pei Zhu, Dong Xu, Li An, He Gao, Xue-Feng Wu, Bing Zhang, Alberto Javier Castro-Tirado, Shashi B. Pandey, Arne Rau, Weihua Lei, Wei Xie, Giancarlo Ghirlanda, Luigi Piro, Paul O’Brien, Eleonora Troja, Peter Jonker, Yun-Wei Yu, Jie An, Run-Chao Chen, Yi-Jing Chen, Xiao-Fei Dong, Rob Eyles-Ferris, Zhou Fan, Shao-Yu Fu, Johan P. U. Fynbo, Xing Gao, Yong-Feng Huang, Shuai-Qing Jiang, Ya-Hui Jiang, Yashaswi Julakanti, Erik Kuulkers, Qing-Hui Lao, Dongyue Li, Zhi-Xing Ling, Xing Liu, Yuan Liu, Jia-Yu Mou, Xin Pan, Varun, Daming Wei, Qinyu Wu, Muskan Yadav, Yu-Han Yang, Weimin Yuan, Shuang-Nan Zhang |
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| Jazyk: | angličtina |
| Rok vydání: | 2024 |
| Předmět: | |
| Zdroj: | The Astrophysical Journal Letters, Vol 975, Iss 2, p L27 (2024) |
| Druh dokumentu: | article |
| ISSN: | 2041-8213 2041-8205 |
| DOI: | 10.3847/2041-8213/ad8652 |
| Popis: | The Einstein Probe (EP) achieved its first detection and localization of a bright X-ray flare, EP240219a, on 2024 February 19, during its commissioning phase. Subsequent targeted searches triggered by the EP240219a alert identified a faint, untriggered gamma-ray burst (GRB) in the archived data of Fermi Gamma-ray Burst Monitor (GBM), Swift Burst Alert Telescope (BAT), and Insight-HXMT/HE. The EP Wide-field X-ray Telescope (WXT) light curve reveals a long duration of approximately 160 s with a slow decay, whereas the Fermi/GBM light curve shows a total duration of approximately 70 s. The peak in the Fermi/GBM light curve occurs slightly later with respect to the peak seen in the EP/WXT light curve. Our spectral analysis shows that a single cutoff power-law (PL) model effectively describes the joint EP/WXT–Fermi/GBM spectra in general, indicating coherent broad emission typical of GRBs. The model yielded a photon index of ∼–1.70 ± 0.05 and a peak energy of ∼257 ± 134 keV. After detection of GRB 240219A, long-term observations identified several candidates in optical and radio wavelengths, none of which was confirmed as the afterglow counterpart during subsequent optical and near-infrared follow-ups. The analysis of GRB 240219A classifies it as an X-ray-rich GRB (XRR) with a high peak energy, presenting both challenges and opportunities for studying the physical origins of X-ray flashes, XRRs, and classical GRBs. Furthermore, linking the cutoff PL component to nonthermal synchrotron radiation suggests that the burst is driven by a Poynting flux-dominated outflow. |
| Databáze: | Directory of Open Access Journals |
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