_version_ 1866915011493888000
author Yin, Yi-Han Iris
Zhang, Bin-Bin
Yang, Jun
Sun, Hui
Zhang, Chen
Shao, Yi-Xuan
Hu, You-Dong
Zhu, Zi-Pei
Xu, Dong
An, Li
Gao, He
Wu, Xue-Feng
Zhang, Bing
Castro-Tirado, Alberto Javier
Pandey, Shashi B.
Rau, Arne
Lei, Weihua
Xie, Wei
Ghirlanda, Giancarlo
Piro, Luigi
O'Brien, Paul
Troja, Eleonora
Jonker, Peter
Yu, Yun-Wei
An, Jie
Chen, Run-Chao
Chen, Yi-Jing
Dong, Xiao-Fei
Eyles-Ferris, Rob
Fan, Zhou
Fu, Shao-Yu
Fynbo, Johan P. U.
Gao, Xing
Huang, Yong-Feng
Jiang, Shuai-Qing
Jiang, Ya-Hui
Julakanti, Yashaswi
Kuulkers, Erik
Lao, Qing-Hui
Li, Dongyue
Ling, Zhi-Xing
Liu, Xing
Liu, Yuan
Mou, Jia-Yu
Pan, Xin
Varun
Wei, Daming
Wu, Qinyu
Yadav, Muskan
Yang, Yu-Han
Yuan, Weimin
Zhang, Shuang-Nan
author_facet Yin, Yi-Han Iris
Zhang, Bin-Bin
Yang, Jun
Sun, Hui
Zhang, Chen
Shao, Yi-Xuan
Hu, You-Dong
Zhu, Zi-Pei
Xu, Dong
An, Li
Gao, He
Wu, Xue-Feng
Zhang, Bing
Castro-Tirado, Alberto Javier
Pandey, Shashi B.
Rau, Arne
Lei, Weihua
Xie, Wei
Ghirlanda, Giancarlo
Piro, Luigi
O'Brien, Paul
Troja, Eleonora
Jonker, Peter
Yu, Yun-Wei
An, Jie
Chen, Run-Chao
Chen, Yi-Jing
Dong, Xiao-Fei
Eyles-Ferris, Rob
Fan, Zhou
Fu, Shao-Yu
Fynbo, Johan P. U.
Gao, Xing
Huang, Yong-Feng
Jiang, Shuai-Qing
Jiang, Ya-Hui
Julakanti, Yashaswi
Kuulkers, Erik
Lao, Qing-Hui
Li, Dongyue
Ling, Zhi-Xing
Liu, Xing
Liu, Yuan
Mou, Jia-Yu
Pan, Xin
Varun
Wei, Daming
Wu, Qinyu
Yadav, Muskan
Yang, Yu-Han
Yuan, Weimin
Zhang, Shuang-Nan
contents 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 $\sim -1.70 \pm 0.05$ and a peak energy of $\sim 257 \pm 134$ 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.
format Preprint
id arxiv_https___arxiv_org_abs_2407_10156
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Triggering the Untriggered: The First Einstein Probe-Detected Gamma-Ray Burst 240219A and Its Implications
Yin, Yi-Han Iris
Zhang, Bin-Bin
Yang, Jun
Sun, Hui
Zhang, Chen
Shao, Yi-Xuan
Hu, You-Dong
Zhu, Zi-Pei
Xu, Dong
An, Li
Gao, He
Wu, Xue-Feng
Zhang, Bing
Castro-Tirado, Alberto Javier
Pandey, Shashi B.
Rau, Arne
Lei, Weihua
Xie, Wei
Ghirlanda, Giancarlo
Piro, Luigi
O'Brien, Paul
Troja, Eleonora
Jonker, Peter
Yu, Yun-Wei
An, Jie
Chen, Run-Chao
Chen, Yi-Jing
Dong, Xiao-Fei
Eyles-Ferris, Rob
Fan, Zhou
Fu, Shao-Yu
Fynbo, Johan P. U.
Gao, Xing
Huang, Yong-Feng
Jiang, Shuai-Qing
Jiang, Ya-Hui
Julakanti, Yashaswi
Kuulkers, Erik
Lao, Qing-Hui
Li, Dongyue
Ling, Zhi-Xing
Liu, Xing
Liu, Yuan
Mou, Jia-Yu
Pan, Xin
Varun
Wei, Daming
Wu, Qinyu
Yadav, Muskan
Yang, Yu-Han
Yuan, Weimin
Zhang, Shuang-Nan
High Energy Astrophysical Phenomena
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 $\sim -1.70 \pm 0.05$ and a peak energy of $\sim 257 \pm 134$ 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.
title Triggering the Untriggered: The First Einstein Probe-Detected Gamma-Ray Burst 240219A and Its Implications
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2407.10156