Fast X-ray transient EP240315A from a Lyman-continuum-leaking galaxy at z ≈ 5

Andrew J. Levan; Peter G. Jonker; Andrea Saccardi; Daniele Bjørn Malesani; Nial R. Tanvir; Luca Izzo; Kasper E. Heintz; Daniel Mata Sánchez; Jonathan Quirola-Vásquez; Manuel A.P. Torres; Susanna D. Vergani; Steve Schulze; Andrea Rossi; Paolo D’Avanzo; Benjamin P. Gompertz; Antonio Martin-Carrillo; Antonio de Ugarte Postigo; Benjamin Schneider; Weimin Yuan; Zhixing Ling; Wenjie Zhang; Xuan Mao; Yuan Liu; Hui Sun; Dong Xu; Zipei Zhu; José Feliciano Agüí Fernández; Lorenzo Amati; Franz E. Bauer; Sergio Campana; Francesco Carotenuto; Ashley Chrimes; Joyce N.D. van Dalen; Valerio D’Elia; Massimo Della Valle; Massimiliano De Pasquale; Vikram S. Dhillon; Lluís Galbany; Nicola Gaspari; Giulia Gianfagna; Andreja Gomboc; Nusrin Habeeb; Dieter Hartmann; Agnes P.C. van Hoof; Youdong Hu; Pall Jakobsson; Yashaswi Julakanti; Judith Korth; Chryssa Kouveliotou; Tanmoy Laskar; Stuart P. Littlefair; Elisabetta Maiorano; Jirong Mao; Andrea Melandri; M. Coleman Miller; Tamal Mukherjee; Samantha R. Oates; Paul O’Brien; Jesse T. Palmerio; Hannu Parviainen; Daniëlle L.A. Pieterse; Silvia Piranomonte; Luigi Piro; Giovanna Pugliese; Maria E. Ravasio; Ben Rayson; Ruben Salvaterra; Rubén Sánchez-Ramírez; Nikhil Sarin; Samuel P.R. Shilling; Rhaana L.C. Starling; Gianpiero Tagliaferri; Aishwarya Linesh Thakur; Christina C. Thöne; Klaas Wiersema; Isabelle Worssam; Tayyaba Zafar

doi:10.1038/s41550-025-02612-9

Fast X-ray transient EP240315A from a Lyman-continuum-leaking galaxy at z ≈ 5

Andrew J. Levan, Peter G. Jonker, Andrea Saccardi, Daniele Bjørn Malesani, Nial R. Tanvir, Luca Izzo, Kasper E. Heintz, Daniel Mata Sánchez, Jonathan Quirola-Vásquez, Manuel A.P. Torres, Susanna D. Vergani, Steve Schulze, Andrea Rossi, Paolo D’Avanzo, Benjamin P. Gompertz, Antonio Martin-Carrillo, Antonio de Ugarte Postigo, Benjamin Schneider, Weimin Yuan, Zhixing LingWenjie Zhang, Xuan Mao, Yuan Liu, Hui Sun, Dong Xu, Zipei Zhu, José Feliciano Agüí Fernández, Lorenzo Amati, Franz E. Bauer, Sergio Campana, Francesco Carotenuto, Ashley Chrimes, Joyce N.D. van Dalen, Valerio D’Elia, Massimo Della Valle, Massimiliano De Pasquale, Vikram S. Dhillon, Lluís Galbany, Nicola Gaspari, Giulia Gianfagna, Andreja Gomboc, Nusrin Habeeb, Dieter Hartmann, Agnes P.C. van Hoof, Youdong Hu, Pall Jakobsson, Yashaswi Julakanti, Judith Korth, Chryssa Kouveliotou, Tanmoy Laskar, Stuart P. Littlefair, Elisabetta Maiorano, Jirong Mao, Andrea Melandri, M. Coleman Miller, Tamal Mukherjee, Samantha R. Oates, Paul O’Brien, Jesse T. Palmerio, Hannu Parviainen, Daniëlle L.A. Pieterse, Silvia Piranomonte, Luigi Piro, Giovanna Pugliese, Maria E. Ravasio, Ben Rayson, Ruben Salvaterra, Rubén Sánchez-Ramírez, Nikhil Sarin, Samuel P.R. Shilling, Rhaana L.C. Starling, Gianpiero Tagliaferri, Aishwarya Linesh Thakur, Christina C. Thöne, Klaas Wiersema, Isabelle Worssam, Tayyaba Zafar

University of Iceland

Research output: Contribution to journal › Article › peer-review

Abstract

The nature of the minute-to-hour-long fast X-ray transients localized by telescopes such as Chandra, Swift and XMM-Newton remains mysterious, with numerous models suggested for the events. Here we report multi-wavelength observations of EP240315a, a 1,600-s-long transient detected by the Einstein Probe, showing it to have a redshift of z = 4.859. We measure a low column density of neutral hydrogen and directly detect leaking ionizing Lyman continuum. The observed properties are consistent with EP240315a being a long-duration gamma-ray burst, and these observations suggest a possible interpretation in which a substantial fraction of the X-ray-transient population are lower-luminosity examples of similar events. If correct, then sensitive narrow-field searches could be a powerful complementary probe to traditional wide-field transient detection in the identification of samples of gamma-ray-burst-like events into the epoch of reionization.

Original language	English
Pages (from-to)	1375-1386
Number of pages	12
Journal	Nature Astronomy
Volume	9
Issue number	9
DOIs	https://doi.org/10.1038/s41550-025-02612-9
Publication status	Published - Sept 2025

Bibliographical note

Publisher Copyright: © The Author(s), under exclusive licence to Springer Nature Limited 2025.

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Levan, A. J., Jonker, P. G., Saccardi, A., Malesani, D. B., Tanvir, N. R., Izzo, L., Heintz, K. E., Mata Sánchez, D., Quirola-Vásquez, J., Torres, M. A. P., Vergani, S. D., Schulze, S., Rossi, A., D’Avanzo, P., Gompertz, B. P., Martin-Carrillo, A., de Ugarte Postigo, A., Schneider, B., Yuan, W., ... Zafar, T. (2025). Fast X-ray transient EP240315A from a Lyman-continuum-leaking galaxy at z ≈ 5. Nature Astronomy, 9(9), 1375-1386. https://doi.org/10.1038/s41550-025-02612-9

@article{f86703eb11d047a38d0684a06b0254ee,

title = "Fast X-ray transient EP240315A from a Lyman-continuum-leaking galaxy at z ≈ 5",

abstract = "The nature of the minute-to-hour-long fast X-ray transients localized by telescopes such as Chandra, Swift and XMM-Newton remains mysterious, with numerous models suggested for the events. Here we report multi-wavelength observations of EP240315a, a 1,600-s-long transient detected by the Einstein Probe, showing it to have a redshift of z = 4.859. We measure a low column density of neutral hydrogen and directly detect leaking ionizing Lyman continuum. The observed properties are consistent with EP240315a being a long-duration gamma-ray burst, and these observations suggest a possible interpretation in which a substantial fraction of the X-ray-transient population are lower-luminosity examples of similar events. If correct, then sensitive narrow-field searches could be a powerful complementary probe to traditional wide-field transient detection in the identification of samples of gamma-ray-burst-like events into the epoch of reionization.",

author = "Levan, \{Andrew J.\} and Jonker, \{Peter G.\} and Andrea Saccardi and Malesani, \{Daniele Bj{\o}rn\} and Tanvir, \{Nial R.\} and Luca Izzo and Heintz, \{Kasper E.\} and \{Mata S{\'a}nchez\}, Daniel and Jonathan Quirola-V{\'a}squez and Torres, \{Manuel A.P.\} and Vergani, \{Susanna D.\} and Steve Schulze and Andrea Rossi and Paolo D{\textquoteright}Avanzo and Gompertz, \{Benjamin P.\} and Antonio Martin-Carrillo and \{de Ugarte Postigo\}, Antonio and Benjamin Schneider and Weimin Yuan and Zhixing Ling and Wenjie Zhang and Xuan Mao and Yuan Liu and Hui Sun and Dong Xu and Zipei Zhu and \{Ag{\"u}{\'i} Fern{\'a}ndez\}, \{Jos{\'e} Feliciano\} and Lorenzo Amati and Bauer, \{Franz E.\} and Sergio Campana and Francesco Carotenuto and Ashley Chrimes and \{van Dalen\}, \{Joyce N.D.\} and Valerio D{\textquoteright}Elia and \{Della Valle\}, Massimo and \{De Pasquale\}, Massimiliano and Dhillon, \{Vikram S.\} and Llu{\'i}s Galbany and Nicola Gaspari and Giulia Gianfagna and Andreja Gomboc and Nusrin Habeeb and Dieter Hartmann and \{van Hoof\}, \{Agnes P.C.\} and Youdong Hu and Pall Jakobsson and Yashaswi Julakanti and Judith Korth and Chryssa Kouveliotou and Tanmoy Laskar and Littlefair, \{Stuart P.\} and Elisabetta Maiorano and Jirong Mao and Andrea Melandri and Miller, \{M. Coleman\} and Tamal Mukherjee and Oates, \{Samantha R.\} and Paul O{\textquoteright}Brien and Palmerio, \{Jesse T.\} and Hannu Parviainen and Pieterse, \{Dani{\"e}lle L.A.\} and Silvia Piranomonte and Luigi Piro and Giovanna Pugliese and Ravasio, \{Maria E.\} and Ben Rayson and Ruben Salvaterra and Rub{\'e}n S{\'a}nchez-Ram{\'i}rez and Nikhil Sarin and Shilling, \{Samuel P.R.\} and Starling, \{Rhaana L.C.\} and Gianpiero Tagliaferri and Thakur, \{Aishwarya Linesh\} and Th{\"o}ne, \{Christina C.\} and Klaas Wiersema and Isabelle Worssam and Tayyaba Zafar",

note = "Publisher Copyright: {\textcopyright} The Author(s), under exclusive licence to Springer Nature Limited 2025.",

year = "2025",

month = sep,

doi = "10.1038/s41550-025-02612-9",

language = "English",

volume = "9",

pages = "1375--1386",

journal = "Nature Astronomy",

issn = "2397-3366",

publisher = "Nature Publishing Group",

number = "9",

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Levan, AJ, Jonker, PG, Saccardi, A, Malesani, DB, Tanvir, NR, Izzo, L, Heintz, KE, Mata Sánchez, D, Quirola-Vásquez, J, Torres, MAP, Vergani, SD, Schulze, S, Rossi, A, D’Avanzo, P, Gompertz, BP, Martin-Carrillo, A, de Ugarte Postigo, A, Schneider, B, Yuan, W, Ling, Z, Zhang, W, Mao, X, Liu, Y, Sun, H, Xu, D, Zhu, Z, Agüí Fernández, JF, Amati, L, Bauer, FE, Campana, S, Carotenuto, F, Chrimes, A, van Dalen, JND, D’Elia, V, Della Valle, M, De Pasquale, M, Dhillon, VS, Galbany, L, Gaspari, N, Gianfagna, G, Gomboc, A, Habeeb, N, Hartmann, D, van Hoof, APC, Hu, Y, Jakobsson, P, Julakanti, Y, Korth, J, Kouveliotou, C, Laskar, T, Littlefair, SP, Maiorano, E, Mao, J, Melandri, A, Miller, MC, Mukherjee, T, Oates, SR, O’Brien, P, Palmerio, JT, Parviainen, H, Pieterse, DLA, Piranomonte, S, Piro, L, Pugliese, G, Ravasio, ME, Rayson, B, Salvaterra, R, Sánchez-Ramírez, R, Sarin, N, Shilling, SPR, Starling, RLC, Tagliaferri, G, Thakur, AL, Thöne, CC, Wiersema, K, Worssam, I & Zafar, T 2025, 'Fast X-ray transient EP240315A from a Lyman-continuum-leaking galaxy at z ≈ 5', Nature Astronomy, vol. 9, no. 9, pp. 1375-1386. https://doi.org/10.1038/s41550-025-02612-9

TY - JOUR

T1 - Fast X-ray transient EP240315A from a Lyman-continuum-leaking galaxy at z ≈ 5

AU - Levan, Andrew J.

AU - Jonker, Peter G.

AU - Saccardi, Andrea

AU - Malesani, Daniele Bjørn

AU - Tanvir, Nial R.

AU - Izzo, Luca

AU - Heintz, Kasper E.

AU - Mata Sánchez, Daniel

AU - Quirola-Vásquez, Jonathan

AU - Torres, Manuel A.P.

AU - Vergani, Susanna D.

AU - Schulze, Steve

AU - Rossi, Andrea

AU - D’Avanzo, Paolo

AU - Gompertz, Benjamin P.

AU - Martin-Carrillo, Antonio

AU - de Ugarte Postigo, Antonio

AU - Schneider, Benjamin

AU - Yuan, Weimin

AU - Ling, Zhixing

AU - Zhang, Wenjie

AU - Mao, Xuan

AU - Liu, Yuan

AU - Sun, Hui

AU - Xu, Dong

AU - Zhu, Zipei

AU - Agüí Fernández, José Feliciano

AU - Amati, Lorenzo

AU - Bauer, Franz E.

AU - Campana, Sergio

AU - Carotenuto, Francesco

AU - Chrimes, Ashley

AU - van Dalen, Joyce N.D.

AU - D’Elia, Valerio

AU - Della Valle, Massimo

AU - De Pasquale, Massimiliano

AU - Dhillon, Vikram S.

AU - Galbany, Lluís

AU - Gaspari, Nicola

AU - Gianfagna, Giulia

AU - Gomboc, Andreja

AU - Habeeb, Nusrin

AU - Hartmann, Dieter

AU - van Hoof, Agnes P.C.

AU - Hu, Youdong

AU - Jakobsson, Pall

AU - Julakanti, Yashaswi

AU - Korth, Judith

AU - Kouveliotou, Chryssa

AU - Laskar, Tanmoy

AU - Littlefair, Stuart P.

AU - Maiorano, Elisabetta

AU - Mao, Jirong

AU - Melandri, Andrea

AU - Miller, M. Coleman

AU - Mukherjee, Tamal

AU - Oates, Samantha R.

AU - O’Brien, Paul

AU - Palmerio, Jesse T.

AU - Parviainen, Hannu

AU - Pieterse, Daniëlle L.A.

AU - Piranomonte, Silvia

AU - Piro, Luigi

AU - Pugliese, Giovanna

AU - Ravasio, Maria E.

AU - Rayson, Ben

AU - Salvaterra, Ruben

AU - Sánchez-Ramírez, Rubén

AU - Sarin, Nikhil

AU - Shilling, Samuel P.R.

AU - Starling, Rhaana L.C.

AU - Tagliaferri, Gianpiero

AU - Thakur, Aishwarya Linesh

AU - Thöne, Christina C.

AU - Wiersema, Klaas

AU - Worssam, Isabelle

AU - Zafar, Tayyaba

PY - 2025/9

Y1 - 2025/9

N2 - The nature of the minute-to-hour-long fast X-ray transients localized by telescopes such as Chandra, Swift and XMM-Newton remains mysterious, with numerous models suggested for the events. Here we report multi-wavelength observations of EP240315a, a 1,600-s-long transient detected by the Einstein Probe, showing it to have a redshift of z = 4.859. We measure a low column density of neutral hydrogen and directly detect leaking ionizing Lyman continuum. The observed properties are consistent with EP240315a being a long-duration gamma-ray burst, and these observations suggest a possible interpretation in which a substantial fraction of the X-ray-transient population are lower-luminosity examples of similar events. If correct, then sensitive narrow-field searches could be a powerful complementary probe to traditional wide-field transient detection in the identification of samples of gamma-ray-burst-like events into the epoch of reionization.

AB - The nature of the minute-to-hour-long fast X-ray transients localized by telescopes such as Chandra, Swift and XMM-Newton remains mysterious, with numerous models suggested for the events. Here we report multi-wavelength observations of EP240315a, a 1,600-s-long transient detected by the Einstein Probe, showing it to have a redshift of z = 4.859. We measure a low column density of neutral hydrogen and directly detect leaking ionizing Lyman continuum. The observed properties are consistent with EP240315a being a long-duration gamma-ray burst, and these observations suggest a possible interpretation in which a substantial fraction of the X-ray-transient population are lower-luminosity examples of similar events. If correct, then sensitive narrow-field searches could be a powerful complementary probe to traditional wide-field transient detection in the identification of samples of gamma-ray-burst-like events into the epoch of reionization.

UR - https://www.scopus.com/pages/publications/105013586742

U2 - 10.1038/s41550-025-02612-9

DO - 10.1038/s41550-025-02612-9

M3 - Article

SN - 2397-3366

VL - 9

SP - 1375

EP - 1386

JO - Nature Astronomy

JF - Nature Astronomy

IS - 9

ER -

Fast X-ray transient EP240315A from a Lyman-continuum-leaking galaxy at z ≈ 5

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