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arXiv · 2404.16425

Soft X-ray prompt emission from a high-redshift gamma-ray burst EP240315a

Y. Liu·H. Sun·D. Xu·D. S. Svinkin·J. Delaunay·N. R. Tanvir·H. Gao·C. Zhang·Y. Chen·X. -F. Wu·B. Zhang·W. Yuan·J. An·G. Bruni·D. D. Frederiks·G. Ghirlanda·J. -W. Hu·A. Li·C. -K. Li·J. -D. Li·D. B. Malesani·L. Piro·G. Raman·R. Ricci·E. Troja·S. D. Vergani·Q. -Y. Wu·J. Yang·B. -B. Zhang·Z. -P. Zhu·A. de Ugarte Postigo·A. G. Demin·D. Dobie·Z. Fan·S. -Y. Fu·J. P. U. Fynbo·J. -J. Geng·G. Gianfagna·Y. -D. Hu·Y. -F. Huang·S. -Q. Jiang·P. G. Jonker·Y. Julakanti·J. A. Kennea·A. A. Kokomov·E. Kuulkers·W. -H. Lei·J. K. Leung·A. J. Levan·D. -Y. Li·Y. Li·S. P. Littlefair·X. Liu·A. L. Lysenko·Y. -N. Ma·A. Martin-Carrillo·P. O'Brien·T. Parsotan·J. Quirola-Vasquez·A. V. Ridnaia·S. Ronchini·A. Rossi·D. Mata-Sanchez·B. Schneider·R. -F. Shen·A. L. Thakur·A. Tohuvavohu·M. A. P. Torres·A. E. Tsvetkova·M. V. Ulanov·J. -J. Wei·D. Xiao·Y. -H. I. Yin·M. Bai·V. Burwitz·Z. -M. Cai·F. -S. Chen·H. -L. Chen·T. -X. Chen·W. Chen·Y. -F. Chen·Y. -H. Chen·H. -Q. Cheng·C. -Z. Cui·W. -W. Cui·Y. -F. Dai·Z. -G. Dai·J. Eder·D. -W. Fan·C. Feldman·H. Feng·Z. Feng·P. Friedrich·X. Gao·J. Guan·D. -W Han·J. Han·D. -J. Hou·H. -B. Hu·T. Hu
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Abstract

Long 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 ($\sim$3600 deg$^2$) and a high sensitivity, EP-WXT captured the earlier engine activation and extended late engine activity through a continuous detection. With a peak X-ray flux at the faint end of previously known high-$z$ GRBs, the detection of EP240315a demonstrates the great potential for EP to study the early universe via GRBs.

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Y. Liu, H. Sun, D. Xu, D. S. Svinkin, J. Delaunay, N. R. Tanvir, H. Gao, C. Zhang, Y. Chen, X. -F. Wu, B. Zhang, W. Yuan, J. An, G. Bruni, D. D. Frederiks, G. Ghirlanda, J. -W. Hu, A. Li, C. -K. Li, J. -D. Li, D. B. Malesani, L. Piro, G. Raman, R. Ricci, E. Troja, S. D. Vergani, Q. -Y. Wu, J. Yang, B. -B. Zhang, Z. -P. Zhu, A. de Ugarte Postigo, A. G. Demin, D. Dobie, Z. Fan, S. -Y. Fu, J. P. U. Fynbo, J. -J. Geng, G. Gianfagna, Y. -D. Hu, Y. -F. Huang, S. -Q. Jiang, P. G. Jonker, Y. Julakanti, J. A. Kennea, A. A. Kokomov, E. Kuulkers, W. -H. Lei, J. K. Leung, A. J. Levan, D. -Y. Li, Y. Li, S. P. Littlefair, X. Liu, A. L. Lysenko, Y. -N. Ma, A. Martin-Carrillo, P. O'Brien, T. Parsotan, J. Quirola-Vasquez, A. V. Ridnaia, S. Ronchini, A. Rossi, D. Mata-Sanchez, B. Schneider, R. -F. Shen, A. L. Thakur, A. Tohuvavohu, M. A. P. Torres, A. E. Tsvetkova, M. V. Ulanov, J. -J. Wei, D. Xiao, Y. -H. I. Yin, M. Bai, V. Burwitz, Z. -M. Cai, F. -S. Chen, H. -L. Chen, T. -X. Chen, W. Chen, Y. -F. Chen, Y. -H. Chen, H. -Q. Cheng, C. -Z. Cui, W. -W. Cui, Y. -F. Dai, Z. -G. Dai, J. Eder, D. -W. Fan, C. Feldman, H. Feng, Z. Feng, P. Friedrich, X. Gao, J. Guan, D. -W Han, J. Han, D. -J. Hou, H. -B. Hu, T. Hu. 2024-04-25. Soft X-ray prompt emission from a high-redshift gamma-ray burst EP240315a. https://arxiv.org/abs/2404.16425

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