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

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 (~3,600°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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Fig. 1: Soft-X-ray image and light curve of the prompt emission from EP-WXT.
Fig. 2: Temporal and spectral behaviours of EP240315a/GRB 240315C during the joint detection by EP-WXT, Swift-BAT and Konus-Wind in epoch 3*.
Fig. 3: The multiwavelength afterglow light curves of EP240315a/GRB 240315C.
Fig. 4: Comparison of EP240315a and Swift GRBs with z > 4.5 in the soft-X-ray band.

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Data availability

The light curves and spectra of EP-WXT, Swift-BAT and Konus-Wind in Figs. 1 and 2 are available on GitHub at https://github.com/liuyuan-naoc/EP240315a.git. The light curves of Swift-BAT GRBs are public and can be found at https://www.swift.ac.uk/burst_analyser.

Code availability

Upon reasonable request, the code (mostly in Python) used to produce the results and figures will be provided.

References

  1. Zhang, B. The Physics of Gamma-Ray Bursts (Cambridge Univ. Press, 2018).

  2. Galama, T. J. et al. An unusual supernova in the error box of the γ-ray burst of 25 April 1998. Nature 395, 670–672 (1998).

    Article  ADS  Google Scholar 

  3. Hjorth, J. et al. A very energetic supernova associated with the γ-ray burst of 29 March 2003. Nature 423, 847–850 (2003).

    Article  ADS  Google Scholar 

  4. Woosley, S. E. & Bloom, J. S. The supernova–gamma-ray burst connection. Annu. Rev. Astron. Astrophys. 44, 507–556 (2006).

    Article  ADS  Google Scholar 

  5. Yüksel, H., Kistler, M. D., Beacom, J. F. & Hopkins, A. M. Revealing the high-redshift star formation rate with gamma-ray bursts. Astrophys. J. Lett. 683, L5 (2008).

    Article  ADS  Google Scholar 

  6. Kistler, M. D., Yüksel, H., Beacom, J. F., Hopkins, A. M. & Wyithe, J. S. B. The star formation rate in the reionization era as indicated by gamma-ray bursts. Astrophys. J. Lett. 705, L104–L108 (2009).

    Article  ADS  Google Scholar 

  7. Fynbo, J. P. U. et al. Probing cosmic chemical evolution with gamma-ray bursts: GRB 060206 at z = 4.048. Astron. Astrophys. 451, L47–L50 (2006).

    Article  ADS  Google Scholar 

  8. Heintz, K. E. et al. Highly ionized metals as probes of the circumburst gas in the natal regions of gamma-ray bursts. Mon. Not. R. Astron. Soc. 479, 3456–3476 (2018).

    Article  ADS  Google Scholar 

  9. Cusumano, G. et al. Huge explosion in the early Universe. Nature 440, 164 (2006).

    Article  ADS  Google Scholar 

  10. Salvaterra, R. et al. GRB090423 at a redshift of z ≈ 8.1. Nature 461, 1258–1260 (2009).

    Article  ADS  Google Scholar 

  11. Cucchiara, A. et al. A photometric redshift of z ~ 9.4 for GRB 090429B. Astrophys. J. 736, 7 (2011).

    Article  ADS  Google Scholar 

  12. Lien, A. et al. The third Swift Burst Alert Telescope gamma-ray burst catalog. Astrophys. J. 829, 7 (2016).

    Article  ADS  Google Scholar 

  13. Yuan, W., Zhang, C., Chen, Y. & Ling, Z. in Handbook of X-Ray and Gamma-Ray Astrophysics (eds Bambi, C. & Santangelo, A.) 1171–1200 (Springer, 2022).

  14. Zhang, W. J. et al. Einstein Probe detected of a fast X-ray transient EP240315a. GCN Circular 35931 (2024).

  15. Gillanders, J. H. et al. Discovery of the optical and radio counterpart to the fast X-ray transient EP240315a. Astrophys. J. Lett. 969, L14 (2024).

    Article  Google Scholar 

  16. Levan, A. J. et al. The fast X-ray transient EP240315a: a z ~ 5 gamma-ray burst in a Lyman continuum leaking galaxy. Preprint at https://doi.org/10.48550/arXiv.2404.16350 (2024).

  17. DeLaunay, J. et al. GRB 240315C/X-ray transient EP240315a: Swift/BAT detection. GCN Circular 35971 (2024).

  18. Svinkin, D. et al. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a). GCN Circular 35972 (2024).

  19. in ’t Zand, J. J. M., Heise, J., van Paradijs, J. & Fenimore, E. E. The prompt X-ray emission of gamma-ray burst 980519. Astrophys. J. Lett. 516, L57–L60 (1999).

    Article  ADS  Google Scholar 

  20. Frontera, F. et al. Prompt and afterglow emission from the X-ray-rich GRB 981226 observed with BeppoSAX. Astrophys. J. 540, 697–703 (2000).

    Article  ADS  Google Scholar 

  21. Piro, L. et al. Probing the environment in gamma-ray bursts: the case of an X-ray precursor, afterglow late onset, and wind versus constant density profile in GRB 011121 and GRB 011211. Astrophys. J. 623, 314–324 (2005).

    Article  ADS  Google Scholar 

  22. D’Alessio, V., Piro, L. & Rossi, E. M. Properties of X-ray rich gamma ray bursts and X-ray flashes detected with BeppoSAX and HETE-2. Astron. Astrophys. 460, 653–664 (2006).

    Article  ADS  Google Scholar 

  23. Galli, A. & Piro, L. Long-term flaring activity of XRF 011030 observed with BeppoSAX. Astron. Astrophys. 455, 413–422 (2006).

    Article  ADS  Google Scholar 

  24. Vetere, L., Soffitta, P., Massaro, E., Giommi, P. & Costa, E. The complete catalogue of GRBs observed by the wide field cameras on board BeppoSAX. Astron. Astrophys. 473, 347–349 (2007).

    Article  ADS  Google Scholar 

  25. Sakamoto, T. et al. Global characteristics of X-ray flashes and X-ray-rich gamma-ray bursts observed by HETE-2. Astrophys. J. 629, 311–327 (2005).

    Article  ADS  Google Scholar 

  26. Amati, L. et al. Intrinsic spectra and energetics of BeppoSAX gamma-ray bursts with known redshifts. Astron. Astrophys. 390, 81–89 (2002).

    Article  ADS  Google Scholar 

  27. Chen, Y. et al. Status of the follow-up x-ray telescope onboard the Einstein Probe satellite. Proc. SPIE 11444, 114445B (2020).

  28. Chen, Y. et al. X-ray transient EP240315a: EP-FXT detection of the X-ray afterglow. GCN Circular 35951 (2024).

  29. Levan, A. J. et al. X-ray transient EP 240315a: Chandra observations. GCN Circular 35963 (2024).

  30. Levan, A. J. et al. X-ray transient EP 240315a: second epoch Chandra observations. GCN Circular 35982 (2024).

  31. Mészáros, P. & Rees, M. J. Optical and long-wavelength afterglow from gamma-ray bursts. Astrophys. J. 476, 232–237 (1997).

    Article  ADS  Google Scholar 

  32. Uhm, Z. L. et al. Dynamics and afterglow light curves of gamma-ray burst blast waves with a long-lived reverse shock. Astrophys. J. 761, 147 (2012).

    Article  ADS  Google Scholar 

  33. Gao, H. et al. A further study of the tBurst of GRBs: rest-frame properties, external plateau contributions, and multiple parameter analysis. Astrophys. J. 845, 51 (2017).

    Article  ADS  Google Scholar 

  34. Zhang, B.-B., Zhang, B., Murase, K., Connaughton, V. & Briggs, M. S. How long does a burst burst? Astrophys. J. 787, 66 (2014).

    Article  ADS  Google Scholar 

  35. Burrows, D. N. et al. Bright X-ray flares in gamma-ray burst afterglows. Science 309, 1833–1835 (2005).

    Article  ADS  Google Scholar 

  36. Zhang, B. et al. Physical processes shaping gamma-ray burst X-ray afterglow light curves: theoretical implications from the Swift X-Ray Telescope observations. Astrophys. J. 642, 354–370 (2006).

    Article  ADS  Google Scholar 

  37. Chincarini, G. et al. The first survey of X-ray flares from gamma-ray bursts observed by Swift: temporal properties and morphology. Astrophys. J. 671, 1903–1920 (2007).

    Article  ADS  Google Scholar 

  38. Troja, E. et al. Swift observations of GRB 070110: an extraordinary X-ray afterglow powered by the central engine. Astrophys. J. 665, 599–607 (2007).

    Article  ADS  Google Scholar 

  39. Romano, P. et al. Panchromatic study of GRB 060124: from precursor to afterglow. Astron. Astrophys. 456, 917–927 (2006).

    Article  ADS  Google Scholar 

  40. Oganesyan, G., Nava, L., Ghirlanda, G. & Celotti, A. Detection of low-energy breaks in gamma-ray burst prompt emission spectra. Astrophys. J. 846, 137 (2017).

    Article  ADS  Google Scholar 

  41. Bromberg, O., Nakar, E., Piran, T. & Sari, R. An observational imprint of the collapsar model of long gamma-ray bursts. Astrophys. J. 749, 110 (2012).

    Article  ADS  Google Scholar 

  42. López-Cámara, D., Lazzati, D. & Morsony, B. J. Three-dimensional simulations of long duration gamma-ray burst jets: timescales from variable engines. Astrophys. J. 826, 180 (2016).

    Article  ADS  Google Scholar 

  43. Geng, J.-J., Zhang, B. & Kuiper, R. Propagation of relativistic, hydrodynamic, intermittent jets in a rotating, collapsing GRB progenitor star. Astrophys. J. 833, 116 (2016).

    Article  ADS  Google Scholar 

  44. Liang, E. W. et al. Testing the curvature effect and internal origin of gamma-ray burst prompt emissions and X-ray flares with Swift data. Astrophys. J. 646, 351–357 (2006).

    Article  ADS  Google Scholar 

  45. Jia, L.-W., Uhm, Z. L. & Zhang, B. A statistical study of GRB X-ray flares: evidence of ubiquitous bulk acceleration in the emission region. Astrophys. J. Suppl. 225, 17 (2016).

    Article  ADS  Google Scholar 

  46. Geng, J.-J., Huang, Y.-F. & Dai, Z.-G. Steep decay of GRB X-ray flares: the results of anisotropic synchrotron radiation. Astrophys. J. Lett. 841, L15 (2017).

    Article  ADS  Google Scholar 

  47. Cheng, H. et al. Ground calibration result of the Lobster Eye Imager for Astronomy. Exp. Astron. 57, 10 (2024).

    Article  ADS  Google Scholar 

  48. Tohuvavohu, A. et al. Gamma-Ray Urgent Archiver for Novel Opportunities (GUANO): Swift/BAT event data dumps on demand to enable sensitive subthreshold GRB searches. Astrophys. J. 900, 35 (2020).

    Article  ADS  Google Scholar 

  49. DeLaunay, J. & Tohuvavohu, A. Harvesting BAT-GUANO with NITRATES (Non-Imaging Transient Reconstruction and Temporal Search): detecting and localizing the faintest gamma-ray bursts with a likelihood framework. Astrophys. J. 941, 169 (2022).

    Article  ADS  Google Scholar 

  50. Aptekar, R. L. et al. Konus-W gamma-ray burst experiment for the GGS Wind spacecraft. Space Sci. Rev. 71, 265–272 (1995).

    Article  ADS  Google Scholar 

  51. Svinkin, D. et al. IPN triangulation of GRB 240315C (consistent with a fast X-ray transient EP240315a). GCN Circular 35966 (2024).

  52. Fan, Z. et al. The Xinglong 2.16-m telescope: current instruments and scientific projects. Publ. Astron. Soc. Pac. 128, 115005 (2016).

    Article  ADS  Google Scholar 

  53. Garzón, F. et al. EMIR, the near-infrared camera and multi-object spectrograph for the GTC. Astron. Astrophys. 667, A107 (2022).

    Article  Google Scholar 

  54. Dhillon, V. S. et al. HiPERCAM: a quintuple-beam, high-speed optical imager on the 10.4-m Gran Telescopio Canarias. Mon. Not. R. Astron. Soc. 507, 350–366 (2021).

    Article  ADS  Google Scholar 

  55. Cepa, J. et al. OSIRIS tunable imager and spectrograph for the GTC. Instrument status. Proc. SPIE 4841, 1739–1749 (2003).

  56. Vernet, J. et al. X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope. Astron. Astrophys. 536, A105 (2011).

    Article  Google Scholar 

  57. Tody, D. The IRAF data reduction and analysis system. Proc. SPIE 627, 733 (1986).

  58. Lang, D., Hogg, D. W., Mierle, K., Blanton, M. & Roweis, S. Astrometry.net: blind astrometric calibration of arbitrary astronomical images. Astron. J. 139, 1782–1800 (2010).

    Article  ADS  Google Scholar 

  59. Chambers, K. C. et al. The Pan-STARRS1 surveys. Preprint at https://doi.org/10.48550/arXiv.1612.05560 (2016).

  60. Flewelling, H. A. et al. The Pan-STARRS1 database and data products. Astrophys. J. Suppl. 251, 7 (2020).

    Article  ADS  Google Scholar 

  61. Skrutskie, M. F. et al. The Two Micron All Sky Survey (2MASS). Astron. J. 131, 1163–1183 (2006).

    Article  ADS  Google Scholar 

  62. Edge, A. et al. The VISTA Kilo-degree Infrared Galaxy (VIKING) survey: bridging the gap between low and high redshift. Messenger 154, 32–34 (2013).

    ADS  Google Scholar 

  63. Sault, R. J., Teuben, P. J. & Wright, M. C. H. A retrospective view of MIRIAD. In Astronomical Data Analysis Software and Systems IV (eds Shaw, R. A. et al.) 433–436 (ASP Conference Series Vol. 77, Astronomical Society of the Pacific, 1995).

  64. Moldon, J. eMCP: e-MERLIN CASA pipeline. Astrophysics Source Code Library ascl:2109.006 (2021).

  65. Willingale, R., Starling, R. L. C., Beardmore, A. P., Tanvir, N. R. & O’Brien, P. T. Calibration of X-ray absorption in our Galaxy. Mon. Not. R. Astron. Soc. 431, 394–404 (2013).

    Article  ADS  Google Scholar 

  66. Salvaterra, R. High redshift gamma-ray bursts. J. High Energy Astrophys. 7, 35–43 (2015).

    Article  ADS  Google Scholar 

  67. Rossi, A. et al. A blast from the infant Universe: the very high-z GRB 210905A. Astron. Astrophys. 665, A125 (2022).

    Article  Google Scholar 

  68. Wilks, S. S. The large-sample distribution of the likelihood ratio for testing composite hypotheses. Ann. Math. Stat. 9, 60–62 (1938).

    Article  Google Scholar 

  69. Svinkin, D. S. et al. The second Konus-Wind catalog of short gamma-ray bursts. Astrophys. J. Suppl. 224, 10 (2016).

    Article  ADS  Google Scholar 

  70. Tsvetkova, A. et al. The Konus-Wind catalog of gamma-ray bursts with known redshifts. II. Waiting-mode bursts simultaneously detected by Swift/BAT. Astrophys. J. 908, 83 (2021).

    Article  ADS  Google Scholar 

  71. Sakamoto, T. et al. Spectral cross-calibration of the Konus-Wind, the Suzaku/WAM, and the Swift/BAT data using gamma-ray bursts. Publ. Astron. Soc. Jpn. 63, 215–277 (2011).

    Article  ADS  Google Scholar 

  72. Cheng, L. X., Ma, Y. Q., Cheng, K. S., Lu, T. & Zhou, Y. Y. The time delay of gamma-ray bursts in the soft energy band. Astron. Astrophys. 300, 746–750 (1995).

    ADS  Google Scholar 

  73. Norris, J. P., Marani, G. F. & Bonnell, J. T. Connection between energy-dependent lags and peak luminosity in gamma-ray bursts. Astrophys. J. 534, 248–257 (2000).

    Article  ADS  Google Scholar 

  74. Band, D. L. Gamma-ray burst spectral evolution through cross-correlations of discriminator light curves. Astrophys. J. 486, 928–937 (1997).

    Article  ADS  Google Scholar 

  75. Lin Lan, H. et al. GRB 221009a: an ordinary nearby GRB with extraordinary observational properties. Astrophys. J. Lett. 949, L4 (2023).

    Article  ADS  Google Scholar 

  76. Xiao, S. et al. Enhanced localization of transients based on a novel cross-correlation method. Astrophys. J. 920, 43 (2021).

    Article  ADS  Google Scholar 

  77. Li, T.-P. et al. Timescale analysis of spectral lags. Chin. J. Astron. Astrophys. 4, 583–598 (2004).

    Article  ADS  Google Scholar 

  78. Zhang, B. et al. Discerning the physical origins of cosmological gamma-ray bursts based on multiple observational criteria: the cases of z = 6.7 GRB 080913, z = 8.2 GRB 090423, and some short/hard GRBs. Astrophys. J. 703, 1696–1724 (2009).

    Article  ADS  Google Scholar 

  79. Minaev, P. Y. & Pozanenko, A. S. The Ep,IEiso correlation: type I gamma-ray bursts and the new classification method. Mon. Not. R. Astron. Soc. 492, 1919–1936 (2020).

    Article  ADS  Google Scholar 

  80. Lelli, F., McGaugh, S. S., Schombert, J. M., Desmond, H. & Katz, H. The baryonic Tully–Fisher relation for different velocity definitions and implications for galaxy angular momentum. Mon. Not. R. Astron. Soc. 484, 3267–3278 (2019).

    Article  ADS  Google Scholar 

  81. Foreman-Mackey, D., Hogg, D. W., Lang, D. & Goodman, J. emcee: the MCMC hammer. Publ. Astron. Soc. Pac. 125, 306–312 (2013).

    Article  ADS  Google Scholar 

  82. Huang, Y. F., Gou, L. J., Dai, Z. G. & Lu, T. Overall evolution of jetted gamma-ray burst ejecta. Astrophys. J. 543, 90–96 (2000).

    Article  ADS  Google Scholar 

  83. Sari, R., Piran, T. & Narayan, R. Spectra and light curves of gamma-ray burst afterglows. Astrophys. J. Lett. 497, L17–L20 (1998).

    Article  ADS  Google Scholar 

  84. Yi, S.-X. et al. Comprehensive study of the X-ray flares from gamma-ray bursts observed by Swift. Astrophys. J. Suppl. 224, 20 (2016).

    Article  ADS  Google Scholar 

  85. Nousek, J. A. et al. Evidence for a canonical gamma-ray burst afterglow light curve in the Swift XRT data. Astrophys. J. 642, 389–400 (2006).

    Article  ADS  Google Scholar 

  86. O’Brien, P. T. et al. The early X-ray emission from GRBs. Astrophys. J. 647, 1213–1237 (2006).

    Article  ADS  Google Scholar 

  87. Rowlinson, A. et al. The unusual X-ray emission of the short Swift GRB 090515: evidence for the formation of a magnetar? Mon. Not. R. Astron. Soc. 409, 531–540 (2010).

    Article  ADS  Google Scholar 

  88. Dainotti, M. G., Willingale, R., Capozziello, S., Fabrizio Cardone, V. & Ostrowski, M. Discovery of a tight correlation for gamma-ray burst afterglows with ‘canonical’ light curves. Astrophys. J. Lett. 722, L215–L219 (2010).

    Article  ADS  Google Scholar 

  89. Xu, M. & Huang, Y. F. New three-parameter correlation for gamma-ray bursts with a plateau phase in the afterglow. Astron. Astrophys. 538, A134 (2012).

    Article  ADS  Google Scholar 

  90. Dainotti, M. G., Postnikov, S., Hernandez, X. & Ostrowski, M. A fundamental plane for long gamma-ray bursts with X-ray plateaus. Astrophys. J. Lett. 825, L20 (2016).

    Article  ADS  Google Scholar 

  91. Cao, S., Dainotti, M. & Ratra, B. Gamma-ray burst data strongly favour the three-parameter fundamental plane (Dainotti) correlation over the two-parameter one. Mon. Not. R. Astron. Soc. 516, 1386–1405 (2022).

    Article  ADS  Google Scholar 

  92. Evans, P. A. et al. The Swift Burst Analyser. I. BAT and XRT spectral and flux evolution of gamma ray bursts. Astron. Astrophys. 519, A102 (2010).

    Article  Google Scholar 

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Acknowledgements

This work is based on the data obtained with EP, a space mission supported by Strategic Priority Program on Space Science of Chinese Academy of Sciences, in collaboration with the European Space Agency, the Max Planck Institute for Extraterrestrial Physics and CNES (grant XDA15310000), the Strategic Priority Research Program of the Chinese Academy of Sciences (grant XDB0550200) and the National Key R&D Program of China (2022YFF0711500). We acknowledge the support by the National Natural Science Foundation of China (grants 12321003, 12103065, 12333004, 12373040, 12021003), the China Manned Space Project (grants CMS-CSST-2021-A13, CMS-CSST-2021-B11) and the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Y2022026, 2023331). We acknowledge the data resources and technical support provided by the China National Astronomical Data Center, the Astronomical Science Data Center of the Chinese Academy of Sciences and the Chinese Virtual Observatory. We acknowledge the observational data taken at the Nordic Optical Telescope (programmes 68-811, principal investigator D.X., and 68-020, principal investigator D.B.M.), the Very Large Telescope (programme 110.24CF, principal investigators N.R.T., S.D.V., D.B.M.), Telescopio Nazionale Galileo (programme A47TAC 42, principal investigator A.M.) and the Large Binocular Telescope (programme IT-2023B-020, PI E.M.). The work of D.S.S., D.D.F., A.V.R., A.L.L., A.E.T., M.V.U., A.G.D. and A.A.K. was carried out in the framework of the basic funding programme of the Ioffe Institute FFUG-2024-0002; A.E.T. also acknowledges financial support from Accordo ASI e INAF HERMES 2022-25-HH.0. P.G.J. has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement 101095973). R.R. and E.T. acknowledge support from the ERC under the European Union’s Horizon 2020 research and innovation programme (grant agreement 101002761). L.P., G.B., G. Gianfagna and A.L.T. acknowledge useful discussions with L. Rhodes regarding the analysis and interpretation of the e-MERLIN dataset. L.P., G.B., G. Gianfagna and A.L.T. acknowledge support from the European Union Horizon 2020 programme under the AHEAD2020 project (grant agreement number 871158). L.P., G. Gianfagna and A.L.T. also acknowledge support from the ASI (Italian Space Agency) through contract 2019-27-HH.0. P.O.’B. and N.R.T. acknowledge support from UK/STFC grant ST/W000857/1. J.D. acknowledges support from NASA contract NAS5-0136. D.B.M. is funded by the European Union (ERC, HEAVYMETAL, 101071865). Views and opinions expressed are, however, those of the authors only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. Y.-D.H. acknowledges financial support from INAF through the GRAWITA Large Program Grant (ID 1.05.12.01.04). D.M.-S. acknowledges support by the Spanish Ministry of Science via the Plan de Generacion de Conocimiento PID2020-120323GB-I00 and PID2021-124879NB-I00. A. Rossi acknowledges support from PRIN-MIUR 2017 (grant 20179ZF5KS). Y.-F.H. acknowledges support from the Xinjiang Tianchi Program.

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W.Y. has been leading the EP project as principal investigator since the mission proposal stage. Y. Liu, H.S., H.G., X.-F. Wu and B.Z. initiated the study. Y. Liu, X.-F. Wu, B.Z., H.G., H.S. and D. Xu coordinated the scientific investigations of the event. Y. Liu, H.S., W.-J.Z., D.-Y.L., J.Y. and Y.-H.I.Y. processed and analysed the WXT data. Q.-Y.W., C.-K.L. and Y.C. processed and analysed the FXT data. J.-W.H. analysed the BAT light curves and simulated the detectability of WXT. J.-D.L., J.A., A.L., Y.-N.M., H.G., D.X. and J.-J.G. performed the multiwavelength afterglow modelling. H.G., X.-F. Wu and B.Z. led the theoretical investigation of the event. J.D. performed the GRB search in Swift/BAT data, as well as developing the likelihood analysis for the spectral fit, light curve and localization. G.R. performed the T90 fit. C.-Y.W. performed the spectral lag calculation. Comments and contributions were provided by the rest of the Swift-BAT GUANO team (J.A.K., T.P., S.R. and A.T.). D.S.S. and D.D.F. performed GRB search in the Konus-Wind data, the high-energy spectral analysis and upper-limit calculations with the contributions of the Konus-Wind team (A.V.R., A.L.L., A.E.T., M.V.U., A.G.D. and A.A.K.). B.-B.Z., J.Y. and Y.-H.I.Y. performed GRB search in Fermi/GBM data. J.Y. and A.L. contributed to the Amati relation. D. Xu, P.G.J., N.R.T., S.D.V., D.B.M., A.J.L., A.d.U.P., S.P.L., A.M.-C., J.Q.-V., A. Rossi, B.S., M.A.P.T., D.M.-S., M.E.R., Y.-D.H. and J.P.U.F. contributed to the optical and near-infrared data taking and analysis and provided comments on the manuscript. R.R., E.T., D.D. and J.K.L. acquired and analysed the Australia Telescope Compact Array data and provided comments on the manuscript. L.P., G.B., A.L.T. and G. Gianfagna contributed to the e-MERLIN radio data acquisition and provided comments on the manuscript. G.B. performed the analysis of the e-MERLIN radio data. Z.-X.L., C.Z., S.-N.Z., X.-J.S., S.-L.S., X.-F.Z., Y.-H.Z., Z.-M.C., F.-S.C. and W.Y. contributed to the development of the WXT instrument. C.Z., Z.-X.L., H.-Q.C., D.-H.Z. and Y. Liu contributed to the calibration of WXT data. Y. Liu, H.-Q.C., C.-C.J., W.-D.Z., D.-Y.L., J.-W.H., H.-Y.L., H.S., H.-W.P. and M.-J.L. contributed to the development of WXT data analysis software. Y.C., S.-M.J., W.-W.C., C.-K.L., D.-W.H., J.W., W.L., Y.-J.Y., Y.-S.W., H.-S.Z., J.G., J.Z., X.-F.Z., J.-J.X., J.M., L.-D.L., H.W., X.-T.Y., T.-X.C., J. Huo, Z.-J.Z., Z.-L.Z., M.-S.L., Y.-X.Z., D.-J.H., L.-M.S., F.-J.L., C.-Z.L., Q.-J.T. and H.-L.C. contributed to the development of the FXT instrument. S.-M.J., H.-S.Z., C.-K.L., J.Z. and J.G. contributed to the development of FXT data analysis software. Y. Liu, H.G., H.S., B.Z., Z.-P.Z., J.-W.H., P.O.’B., Y.J. and D. Xu contributed to the interpretation of the observations and the writing of the manuscript with contributions from all authors.

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Correspondence to H. Gao, C. Zhang, Y. Chen or X.-F. Wu.

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Extended data

Extended Data Fig. 1 The upper limits (15–350 keV) of BAT and Konus-Wind in the epochs without gamma-ray detection.

The extrapolated fluxes (with 1σ uncertainty) from the WXT spectra are also shown for comparison and well below the upper limits in these epochs.

Supplementary information

Supplementary Information

Supplementary Figs. 1–3 and Tables 1–5.

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Liu, Y., Sun, H., Xu, D. et al. Soft X-ray prompt emission from the high-redshift gamma-ray burst EP240315a. Nat Astron 9, 564–576 (2025). https://doi.org/10.1038/s41550-024-02449-8

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