Liu, Y.Sun, H.Xu, D.Svinkin, D. S.Delaunay, J.Tanvir, N. R.Gao, H.Zhang, C.Chen, Y.Wu, X.-F.Zhang, B.Yuan, W.An, J.Bruni, G.Frederiks, D. D.Ghirlanda, G.Hu, J.-W.Li, A.Li, C.-K.Li, J.-D.Malesani, D. B.Piro, L.Raman, G.Ricci, R.Troja, E.Vergani, S. D.Wu, Q.-Y.Yang, J.Zhang, B.-B.Zhu, Z.-P.Postigo, A. de UgarteDemin, A. G.Dobie, D.Fan, Z.Fu, S.-Y.Fynbo, J. P. U.Geng, J.-J.Gianfagna, G.Hu, Y.-D.Huang, Y.-F.Jiang, S.-Q.Jonker, P. G.Julakanti, Y.Kennea, J. A.Kokomov, A. A.Kuulkers, E.Lei, W.-H.Leung, J. K.Levan, A. J.Li, D.-Y.Li, Y.Littlefair, S. P.Liu, X.Lysenko, A. L.Ma, Y.-N.Martin-Carrillo, A.O'Brien, P.Parsotan, TylerQuirola-Vasquez, J.Ridnaia, A. V.Ronchini, S.Rossi, A.Mata-Sanchez, D.Schneider, B.Shen, R.-F.Thakur, A. L.Tohuvavohu, A.Torres, M. A. P.Tsvetkova, A. E.Ulanov, M. V.Wei, J.-J.Xiao, D.Yin, Y.-H. I.Bai, M.Burwitz, V.Cai, Z.-M.Chen, F.-S.Chen, H.-L.Chen, T.-X.Chen, W.Chen, Y.-F.Chen, Y.-H.Cheng, H.-Q.Cui, C.-Z.Cui, W.-W.Dai, Y.-F.Dai, Z.-G.Eder, J.Fan, D.-W.Feldman, C.Feng, H.Feng, Z.Friedrich, P.Gao, X.Guan, J.Han, D.-W.Han, J.Hou, D.-J.Hu, H.-B.Hu, T.Huang, M.-H.Huo, J.Hutchinson, I.Ji, Z.Jia, S.-M.Jia, Z.-Q.Jiang, B.-W.Jin, C.-C.Jin, G.Jin, J.-J.Keereman, A.Lerman, H.Li, J.-F.Li, L.-H.Li, M.-S.Li, W.Li, Z.-D.Lian, T.-Y.Liang, E.-W.Ling, Z.-X.Liu, C.-Z.Liu, H.-Y.Liu, H.-Q.Liu, M.-J.Liu, Y.-R.Lu, F.-J.LU, H.-J.Luo, L.-D.Ma, F. L.Ma, J.Mao, J.-R.Mao, X.McHugh, M.Meidinger, N.Nandra, K.Osborne, J. P.Pan, H.-W.Pan, X.Ravasio, M. E.Rau, A.Rea, N.Rehman, U.Sanders, J.Santovincenzo, A.Song, L.-M.Su, J.Sun, L.-J.Sun, S.-L.Sun, X.-J.Tan, Y.-Y.Tang, Q.-J.Tao, Y.-H.Tong, J.-Z.Wang, H.Wang, J.Wang, L.Wang, W.-X.Wang, X.-F.Wang, X.-Y.Wang, Y.-L.Wang, Y.-S.Wei, D.-M.Willingale, R.Xiong, S.-L.Xu, H.-T.Xu, J.-J.Xu, X.-P.Xu, Y.-F.Xu, Z.Xue, C.-B.Xue, Y.-L.Yan, A.-L.Yang, F.Yang, H.-N.Yang, X.-T.Yang, Y.-J.Yu, Y.-W.Zhang, J.Zhang, M.Zhang, S.-N.Zhang, W.-D.Zhang, W.-J.Zhang, Y.-H.Zhang, Z.Zhang, Z.Zhang, Z.-L.Zhao, D.-H.Zhao, H.-S.Zhao, X.-F.Zhao, Z.-J.Zhou, L.-X.Zhou, Y.-L.Zhu, Y.-X.Zhu, Z.-C.Zuo, X.-X.2024-05-132024-05-132024-04-25https://doi.org/10.48550/arXiv.2404.16425http://hdl.handle.net/11603/33932Long gamma-ray bursts (GRBs) are believed to originate from core collapse of massive stars. High-redshift GRBs can probe the star formation and reionization history of the early universe, but their detection remains rare. Here we report the detection of a GRB triggered in the 0.5--4 keV band by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated as EP240315a, whose bright peak was also detected by the Swift Burst Alert Telescope and Konus-Wind through off-line analyses. At a redshift of z=4.859, EP240315a showed a much longer and more complicated light curve in the soft X-ray band than in gamma-rays. Benefiting from a large field-of-view (∼3600 deg²) and a high sensitivity, EP-WXT captured the earlier engine activation and extended late engine activity through a continuous detection. With a peak X-ray flux at the faint end of previously known high-z GRBs, the detection of EP240315a demonstrates the great potential for EP to study the early universe via GRBs.41 pagesen-USCC BY-NC-ND 4.0 DEED Attribution-NonCommercial-NoDerivs 4.0 InternationalAstrophysics - High Energy Astrophysical PhenomenaText