XRF 241001A/SN 2024aiiq: A faint soft X-ray transient detected by SVOM with a broad-line type Ic supernova revealed by JWST
Year: 2026
Type: article
Abstract: Context. X-ray flashes (XRFs) are a type of gamma-ray burst (GRB) with prompt emission predominantly below ∼30 keV and have been poorly detected by previous missions monitoring the high-energy sky. The advent of the Space-based multiband astronomical Variable Objects Monitor (SVOM), with its wide-field instrument ECLAIRs, provides a new way to detect soft X-ray transients such as XRFs, complemented by rapid onboard multiwavelength follow-up. Aims. We present photometric and spectroscopic observations of XRF 241001A detected by SVOM, a soft, subluminous, and low-energetic burst located in a poorly populated region of the Amati relation. We investigated the origin of its faint, soft high-energy emission to assess its connection to the long GRB population. Methods. We analyzed the SVOM/ECLAIRs prompt emission and modeled its afterglow emission from X-ray-to-radio. We present JWST /NIRSpec and SVOM/VT observations of the associated supernova (SN 2024aiiq), which we modeled with an Arnett radioactive decay component, and we compared its properties with previously detected GRB/SNe. Results. The event XRF 241001A is located at z = 0.573 and has a prompt emission dominated by photons below 20 keV, with a duration of T 90 = 3.14 seconds. Its spectrum is consistent with both thermal and nonthermal models, each implying a low E peak < 10 keV and E iso ∼ 8 × 10 49 erg. The X-ray-to-radio afterglow modeling favors an origin from a relativistic jet viewed on-axis and supports a nonthermal origin of the prompt emission. In the optical, XRF 241001A exhibits an early blue emission, similar to that detected in some extragalactic fast X-ray transients (eFXTs) and inconsistent with the expected synchrotron emission from a relativistic jet. The JWST /NIRSpec observations firmly established its collapsar origin by revealing an SN Type Ic with broad lines, comparable to SN 1998bw and SN 2025kg-like events near maximum light and with similar properties. Conclusions. The event XRF 241001A is a soft low-luminosity collapsar event produced by a weak relativistic jet observed on-axis, supporting the view that at least part of the XRF population forms the low-energy soft tail of the long GRB population. Its observation demonstrates the potential of SVOM/ECLAIRs to probe the soft regime of the high-energy transient population that remains largely unexplored.
Source: Astronomy and Astrophysics
Authors: B. Schneider, M. Brunet, B. P. Gompertz, D. Turpin, D. B. Malesani, O. Godet, A. J. Levan, F. Daigne, N. Sarin, N. A. Rakotondrainibe, A. Martin-Carrillo, J. T. Palmerio, C. C. Thöne, H. L. Li, A. Saccardi, A. de Ugarte Postigo, S. Antier, V. Buat, D. Ďurovčíková, L. Izzo, J. K. Leung, G. Mo, Y. L. Qiu, S. D. Vergani, J. Wang, J. Y. Wei, L. P. Xin, R. Mochkovitch, B. Zhang, H. B. Cai, S. Campana, A. Coleiro, B. Cordier, P. D’Avanzo, N. Dagoneau, V. D’Elia, Y. W. Dong, D. Götz, S. Guillot, X. H. Han, D. H. Hartmann, L. Huang, Y. F. Huang, P. Jakobsson, A. Klotz, C. Lachaud, E. Le Floc’h, X. M. Lu, P. Maggi, M. De Pasquale, F. Piron, R. Salvaterra, S. Schanne, J. Sollerman, N. R. Tanvir, Z. Vidadi, P. Wang, C. Wu, S. L. Xiong, Y. Xu, T. Zafar, P. P. Zhang, S. N. Zhang, S. J. Zheng
Institutions: Centre National de la Recherche Scientifique, Aix-Marseille Université, Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, University of Birmingham, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CEA Paris-Saclay - Etablissement de Saclay, CEA Paris-Saclay, Institut de Recherche sur les Lois Fondamentales de l'Univers, University of Copenhagen, Radboud University Nijmegen, University of Warwick, Institut Universitaire de France, Institut d'Astrophysique de Paris, Sorbonne Université, University of Cambridge, University College Dublin, Evgeni Kharadze Georgian National Astrophysical Observatory, Chinese Academy of Sciences, National Astronomical Observatories, Centre National d'Études Spatiales, Université Paris-Saclay, Institut National de Physique Nucléaire et de Physique des Particules, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie, Massachusetts Institute of Technology, Astronomical Observatory of Capodimonte, National Institute for Astrophysics, University of Toronto, Hebrew University of Jerusalem, California Institute of Technology, Carnegie Institution for Science, Université Paris Sciences et Lettres, Observatoire de Paris, University of Chinese Academy of Sciences, University of Nevada, Reno, University of Hong Kong, Brera Astronomical Observatory, Université Paris Cité, University of Insubria, Agenzia Spaziale Italiana, Institute of High Energy Physics, Clemson University, Nanjing University, University of Iceland, Observatoire astronomique de Strasbourg, Université de Strasbourg, University of Messina, Université de Montpellier, Laboratoire Univers et Particules de Montpellier, Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano, Stockholm University, University of Leicester, Azerbaijan National Academy of Sciences, Shamakhy Astrophysical Observatory named after Nasraddin Tusi, Macquarie University
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: National Aeronautics and Space Administration, Space Telescope Science Institute, Australian Government, Leverhulme Trust, University of Leicester, European Commission, Commonwealth Scientific and Industrial Research Organisation, National Research Foundation, Agence Nationale de la Recherche, Danmarks Grundforskningsfond, National Natural Science Foundation of China, Chinese Academy of Sciences, Centre National d’Etudes Spatiales, Nuclear Safety and Security Commission, European Southern Observatory, Centre National de la Recherche Scientifique, Science and Technology Facilities Council, Xi'an Institute of Optics and Precision Mechanics, Institute of High Energy Physics, National Astronomical Observatories, Chinese Academy of Sciences
Awards: G103270039, G1338664626, G1532879105, G1595234129, G2508734708, G256731684, G2627914446, G271529020, G2929489430, G3059499108, Cosmic Dawn Center (DAWN), G4330545635, G5178316636, G534390765, G5568641063, Unveiling the Local Population of Compact Binary Mergers, Novel probes of the distant universe using GRBs, G6217448592, G6232308387, Probing and Exploring high-redshift Galaxies Spectroscopically Using Svom gamma-ray bursts, Astrophysics Research at the University of Leicester, G7080048889, G7667335384, G8330833215
OpenAlex ID: W7201850279