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An extremely soft and weak fast X-ray transient associated with a luminous supernova

Fuente: arXiv

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Main Authors:	Li, W. -X., Zhu, Z. -P., Zou, X. -Z., Geng, J. -J., Liu, L. -D., Wang, Y. -H., Li, R. -Z., Xu, D., Sun, H., Wang, X. -F., Yu, Y. -W., Zhang, B., Wu, X. -F., Yang, Y., Filippenko, A. V., Liu, X. -W., Yuan, W. -M., Aguado, D., An, J., An, T., Buckley, D. A. H., Castro-Tirado, A. J., Fu, S. -Y., Fynbo, J. P. U., Howell, D. A., Hu, J. -W., Jiang, S. -Q., Kumar, A., Mao, J. -R., Maund, J. R., Liu, X., Mockler, B., Moskvitin, A., Andrews, M., Bom, C. R., Brink, T. G., Chatterjee, K., Chen, Y., Cheng, H. -Q., Cooke, J., Dai, J. L., Du, G. -W., Erasmus, N., Fang, Y., Farah, J., Goranskij, V., Gritsevich, M., Gu, M., Guo, Z., Hsiao, E., Hu, Y. -D., Hua, Y. -L., Jacobson-Galán, W., Jia, S. -M., Jin, C. -C., Kasliwal, M. M., Kilpatrick, C. D., Kumar, B., Lei, W. -H., Li, C. -K., Li, D. -Y., Li, L. -P., Ling, Z. -X., Liu, Q. -C., Liu, Y., Liu, Y. -Q., López-Oramas, A., Maslennikova, O., McCully, C., Monageng, I., Newsone, M., Gonzalez, E. Padilla, Pan, H. -W., Peng, H. -W., Pignata, G., Poidevin, F., Potter, S. B., Pérez-Fournon, I., Santana-Silva, L., Santos, A., Song, C. -Y., Song, F. -F., Spiridonova, O., Sun, N. -C., Sun, X. -J., Terreran, G., Wang, L. -Z., Wang, L. -F., Wang, B. -T., Wang, Z. -Y., Wu, G. -L., Xiang, D. -F., Xiao, H. -F., Xu, Y. -F., Xue, S. -J., Yan, S. -Y., Yang, Y. -P., Yu, L. -X., Zhang, Y. -H., Zhang, C., Zhang, J. -H., Zhang, J. -J., Zheng, W., Zou, H.
Format:	Preprint
Published:	2025
Subjects:	High Energy Astrophysical Phenomena
Online Access:	Acceder al recurso
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author	Li, W. -X. Zhu, Z. -P. Zou, X. -Z. Geng, J. -J. Liu, L. -D. Wang, Y. -H. Li, R. -Z. Xu, D. Sun, H. Wang, X. -F. Yu, Y. -W. Zhang, B. Wu, X. -F. Yang, Y. Filippenko, A. V. Liu, X. -W. Yuan, W. -M. Aguado, D. An, J. An, T. Buckley, D. A. H. Castro-Tirado, A. J. Fu, S. -Y. Fynbo, J. P. U. Howell, D. A. Hu, J. -W. Jiang, S. -Q. Kumar, A. Mao, J. -R. Maund, J. R. Liu, X. Mockler, B. Moskvitin, A. Andrews, M. Bom, C. R. Brink, T. G. Chatterjee, K. Chen, Y. Cheng, H. -Q. Cooke, J. Dai, J. L. Du, G. -W. Erasmus, N. Fang, Y. Farah, J. Goranskij, V. Gritsevich, M. Gu, M. Guo, Z. Hsiao, E. Hu, Y. -D. Hua, Y. -L. Jacobson-Galán, W. Jia, S. -M. Jin, C. -C. Kasliwal, M. M. Kilpatrick, C. D. Kumar, B. Lei, W. -H. Li, C. -K. Li, D. -Y. Li, L. -P. Ling, Z. -X. Liu, Q. -C. Liu, Y. Liu, Y. -Q. López-Oramas, A. Maslennikova, O. McCully, C. Monageng, I. Newsone, M. Gonzalez, E. Padilla Pan, H. -W. Peng, H. -W. Pignata, G. Poidevin, F. Potter, S. B. Pérez-Fournon, I. Santana-Silva, L. Santos, A. Song, C. -Y. Song, F. -F. Spiridonova, O. Sun, N. -C. Sun, X. -J. Terreran, G. Wang, L. -Z. Wang, L. -F. Wang, B. -T. Wang, Z. -Y. Wu, G. -L. Xiang, D. -F. Xiao, H. -F. Xu, Y. -F. Xue, S. -J. Yan, S. -Y. Yang, Y. -P. Yu, L. -X. Zhang, Y. -H. Zhang, Y. -H. Zhang, C. Zhang, J. -H. Zhang, J. -J. Zheng, W. Zou, H.
author_facet	Li, W. -X. Zhu, Z. -P. Zou, X. -Z. Geng, J. -J. Liu, L. -D. Wang, Y. -H. Li, R. -Z. Xu, D. Sun, H. Wang, X. -F. Yu, Y. -W. Zhang, B. Wu, X. -F. Yang, Y. Filippenko, A. V. Liu, X. -W. Yuan, W. -M. Aguado, D. An, J. An, T. Buckley, D. A. H. Castro-Tirado, A. J. Fu, S. -Y. Fynbo, J. P. U. Howell, D. A. Hu, J. -W. Jiang, S. -Q. Kumar, A. Mao, J. -R. Maund, J. R. Liu, X. Mockler, B. Moskvitin, A. Andrews, M. Bom, C. R. Brink, T. G. Chatterjee, K. Chen, Y. Cheng, H. -Q. Cooke, J. Dai, J. L. Du, G. -W. Erasmus, N. Fang, Y. Farah, J. Goranskij, V. Gritsevich, M. Gu, M. Guo, Z. Hsiao, E. Hu, Y. -D. Hua, Y. -L. Jacobson-Galán, W. Jia, S. -M. Jin, C. -C. Kasliwal, M. M. Kilpatrick, C. D. Kumar, B. Lei, W. -H. Li, C. -K. Li, D. -Y. Li, L. -P. Ling, Z. -X. Liu, Q. -C. Liu, Y. Liu, Y. -Q. López-Oramas, A. Maslennikova, O. McCully, C. Monageng, I. Newsone, M. Gonzalez, E. Padilla Pan, H. -W. Peng, H. -W. Pignata, G. Poidevin, F. Potter, S. B. Pérez-Fournon, I. Santana-Silva, L. Santos, A. Song, C. -Y. Song, F. -F. Spiridonova, O. Sun, N. -C. Sun, X. -J. Terreran, G. Wang, L. -Z. Wang, L. -F. Wang, B. -T. Wang, Z. -Y. Wu, G. -L. Xiang, D. -F. Xiao, H. -F. Xu, Y. -F. Xue, S. -J. Yan, S. -Y. Yang, Y. -P. Yu, L. -X. Zhang, Y. -H. Zhang, Y. -H. Zhang, C. Zhang, J. -H. Zhang, J. -J. Zheng, W. Zou, H.
contents	Long gamma-ray bursts (LGRBs), including their subclasses of low-luminosity GRBs (LL-GRBs) and X-ray flashes (XRFs) characterized by low spectral peak energies, are known to be associated with broad-lined Type Ic supernovae (SNe Ic-BL), which result from the core collapse of massive stars that lose their outer hydrogen and helium envelopes. However, the soft and weak end of the GRB/XRF population remains largely unexplored, due to the limited sensitivity to soft X-ray emission. Here we report the discovery of a fast X-ray transient, EP250108a, detected by the Einstein Probe (EP) in the soft X-ray band at redshift $z = 0.176$, which was followed up by extensive multiband observations. EP250108a shares similar X-ray luminosity as XRF\,060218, the prototype of XRFs, but it extends GRBs/XRFs down to the unprecedentedly soft and weak regimes, with its $E_{\rm peak} \lesssim 1.8\,\mathrm{keV}$ and $E_{\rm iso} \lesssim 10^{49}\, \mathrm{erg}$, respectively. Meanwhile, EP250108a is found to be associated with SN\,2025kg, one of the most luminous and possibly magnetar-powered SNe Ic-BL detected so far. Modeling of the well-sampled optical light curves favors a mildly relativistic outflow as the origin of this event. This discovery demonstrates that EP, with its unique capability, is opening a new observational window into the diverse outcomes of death of massive stars.
format	Preprint
id	arxiv_https___arxiv_org_abs_2504_17034
institution	arXiv
publishDate	2025
record_format	arxiv
spellingShingle	An extremely soft and weak fast X-ray transient associated with a luminous supernova Li, W. -X. Zhu, Z. -P. Zou, X. -Z. Geng, J. -J. Liu, L. -D. Wang, Y. -H. Li, R. -Z. Xu, D. Sun, H. Wang, X. -F. Yu, Y. -W. Zhang, B. Wu, X. -F. Yang, Y. Filippenko, A. V. Liu, X. -W. Yuan, W. -M. Aguado, D. An, J. An, T. Buckley, D. A. H. Castro-Tirado, A. J. Fu, S. -Y. Fynbo, J. P. U. Howell, D. A. Hu, J. -W. Jiang, S. -Q. Kumar, A. Mao, J. -R. Maund, J. R. Liu, X. Mockler, B. Moskvitin, A. Andrews, M. Bom, C. R. Brink, T. G. Chatterjee, K. Chen, Y. Cheng, H. -Q. Cooke, J. Dai, J. L. Du, G. -W. Erasmus, N. Fang, Y. Farah, J. Goranskij, V. Gritsevich, M. Gu, M. Guo, Z. Hsiao, E. Hu, Y. -D. Hua, Y. -L. Jacobson-Galán, W. Jia, S. -M. Jin, C. -C. Kasliwal, M. M. Kilpatrick, C. D. Kumar, B. Lei, W. -H. Li, C. -K. Li, D. -Y. Li, L. -P. Ling, Z. -X. Liu, Q. -C. Liu, Y. Liu, Y. -Q. López-Oramas, A. Maslennikova, O. McCully, C. Monageng, I. Newsone, M. Gonzalez, E. Padilla Pan, H. -W. Peng, H. -W. Pignata, G. Poidevin, F. Potter, S. B. Pérez-Fournon, I. Santana-Silva, L. Santos, A. Song, C. -Y. Song, F. -F. Spiridonova, O. Sun, N. -C. Sun, X. -J. Terreran, G. Wang, L. -Z. Wang, L. -F. Wang, B. -T. Wang, Z. -Y. Wu, G. -L. Xiang, D. -F. Xiao, H. -F. Xu, Y. -F. Xue, S. -J. Yan, S. -Y. Yang, Y. -P. Yu, L. -X. Zhang, Y. -H. Zhang, Y. -H. Zhang, C. Zhang, J. -H. Zhang, J. -J. Zheng, W. Zou, H. High Energy Astrophysical Phenomena Long gamma-ray bursts (LGRBs), including their subclasses of low-luminosity GRBs (LL-GRBs) and X-ray flashes (XRFs) characterized by low spectral peak energies, are known to be associated with broad-lined Type Ic supernovae (SNe Ic-BL), which result from the core collapse of massive stars that lose their outer hydrogen and helium envelopes. However, the soft and weak end of the GRB/XRF population remains largely unexplored, due to the limited sensitivity to soft X-ray emission. Here we report the discovery of a fast X-ray transient, EP250108a, detected by the Einstein Probe (EP) in the soft X-ray band at redshift $z = 0.176$, which was followed up by extensive multiband observations. EP250108a shares similar X-ray luminosity as XRF\,060218, the prototype of XRFs, but it extends GRBs/XRFs down to the unprecedentedly soft and weak regimes, with its $E_{\rm peak} \lesssim 1.8\,\mathrm{keV}$ and $E_{\rm iso} \lesssim 10^{49}\, \mathrm{erg}$, respectively. Meanwhile, EP250108a is found to be associated with SN\,2025kg, one of the most luminous and possibly magnetar-powered SNe Ic-BL detected so far. Modeling of the well-sampled optical light curves favors a mildly relativistic outflow as the origin of this event. This discovery demonstrates that EP, with its unique capability, is opening a new observational window into the diverse outcomes of death of massive stars.
title	An extremely soft and weak fast X-ray transient associated with a luminous supernova
topic	High Energy Astrophysical Phenomena
url	https://arxiv.org/abs/2504.17034