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arXiv · 2509.25877

A fast powerful X-ray transient from possible tidal disruption of a white dwarf

Dongyue Li·Wenda Zhang·Jun Yang·Jin-Hong Chen·Weimin Yuan·Huaqing Cheng·Fan Xu·Xinwen Shu·Rong-Feng Shen·Ning Jiang·Jiazheng Zhu·Chang Zhou·Weihua Lei·Hui Sun·Chichuan Jin·Lixin Dai·Bing Zhang·Yu-Han Yang·Wenjie Zhang·Hua Feng·Bifang Liu·Hongyan Zhou·Haiwu Pan·Mingjun Liu·Stephane Corbel·Sitha K. Jagan·Maria Cristina Baglio·Christopher R. Burns·Floriane Cangemi·Chun Chen·Yehao Cheng·Alexis Coleiro·Francesco Coti Zelati·Sourya R. Das·Zhongnan Dong·Luis Galbany·Noa Grollimund·Daniel Kelson·Dong Lai·Xia Li·Yuan Liu·Alessio Marino·Brenna Mockler·Paul O'Brien·Erlin Qiao·Nanda Rea·Resmi·Jérome Rodriguez·Richard Saxton·Luming Sun·Lian Tao·Tinggui Wang·Yilong Wang·Xuefeng Wu·Dong Xu·Yijia Zhang·Guoying Zhao·Congying Bao·Zhiming Cai·Yehai Chen·Yong Chen·Bertrand Cordier·Chenzhou Cui·Weiwei Cui·Zhou Fan·He Gao·Giancarlo Ghirlanda·Ju Guan·Dawei Han·Jinxin Hao·Jingwei Hu·Maohai Huang·Yong-Feng Huang·Shumei Jia·Ge Jin·Stefanie Komossa·Chengkui Li·Zhixing Ling·Congzhan Liu·Heyang Liu·Huaqiu Liu·Fangjun Lu·Kirpal Nandra·Jan-Uwe Ness·Arne Rau·Jeremy Sanders·Liming Song·Roberto Soria·Shengli Sun·Xiaojin Sun·Yuyin Tan·Eleonora Troja·Sixiang Wen·Haitao Xu·Changbin Xue·Yongquan Xue·Yi-Han Iris Yin·Chen Zhang·Shuang-Nan Zhang·Yonghe Zhang
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Abstract

Stars captured by black holes (BHs) can be torn apart by strong tidal forces, producing electromagnetic flares. To date, more than 100 tidal disruption events (TDEs) have been observed, each involving invariably normal gaseous stars whose debris falls onto the BH, sustaining the flares over years. White dwarfs (WDs), which are the most prevalent compact stars and a million times denser--and therefore tougher--than gaseous stars, can only be disrupted by intermediate-mass black holes (IMBHs) of 10^2--10^5 solar masses. WD-TDEs are considered to generate more powerful and short-lived flares, but their evidence has been lacking. Here we report observations of a fast and luminous X-ray transient EP250702a detected by Einstein Probe. Its one-day-long X-ray peak as luminous as 10^(47-49) erg/s showed strong recurrent flares with hard spectra extending to several tens of MeV gamma-rays, as detected by Fermi/GBM and Konus-Wind, indicating relativistic jet emission. The jet's X-ray dropped sharply from 3 x 10^49 erg/s to around 10^44 erg/s within 20 days (10 days in the source rest frame). These characteristics are inconsistent with any known transient phenomena other than a jetted-TDE evolving over an unprecedentedly short timescale, indicating the disruption of a WD by an IMBH. At late times, a new soft component progressively dominates the X-ray spectrum, exhibiting an extreme super-Eddington luminosity, which possibly originates from an accretion disc. WD-TDEs open a new window for investigating the elusive IMBHs and their surrounding stellar environments, and they are prime sources of gravitational waves in the band of space-based interferometers.

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Dongyue Li, Wenda Zhang, Jun Yang, Jin-Hong Chen, Weimin Yuan, Huaqing Cheng, Fan Xu, Xinwen Shu, Rong-Feng Shen, Ning Jiang, Jiazheng Zhu, Chang Zhou, Weihua Lei, Hui Sun, Chichuan Jin, Lixin Dai, Bing Zhang, Yu-Han Yang, Wenjie Zhang, Hua Feng, Bifang Liu, Hongyan Zhou, Haiwu Pan, Mingjun Liu, Stephane Corbel, Sitha K. Jagan, Maria Cristina Baglio, Christopher R. Burns, Floriane Cangemi, Chun Chen, Yehao Cheng, Alexis Coleiro, Francesco Coti Zelati, Sourya R. Das, Zhongnan Dong, Luis Galbany, Noa Grollimund, Daniel Kelson, Dong Lai, Xia Li, Yuan Liu, Alessio Marino, Brenna Mockler, Paul O'Brien, Erlin Qiao, Nanda Rea, Resmi, Jérome Rodriguez, Richard Saxton, Luming Sun, Lian Tao, Tinggui Wang, Yilong Wang, Xuefeng Wu, Dong Xu, Yijia Zhang, Guoying Zhao, Congying Bao, Zhiming Cai, Yehai Chen, Yong Chen, Bertrand Cordier, Chenzhou Cui, Weiwei Cui, Zhou Fan, He Gao, Giancarlo Ghirlanda, Ju Guan, Dawei Han, Jinxin Hao, Jingwei Hu, Maohai Huang, Yong-Feng Huang, Shumei Jia, Ge Jin, Stefanie Komossa, Chengkui Li, Zhixing Ling, Congzhan Liu, Heyang Liu, Huaqiu Liu, Fangjun Lu, Kirpal Nandra, Jan-Uwe Ness, Arne Rau, Jeremy Sanders, Liming Song, Roberto Soria, Shengli Sun, Xiaojin Sun, Yuyin Tan, Eleonora Troja, Sixiang Wen, Haitao Xu, Changbin Xue, Yongquan Xue, Yi-Han Iris Yin, Chen Zhang, Shuang-Nan Zhang, Yonghe Zhang. 2025-12-23. A fast powerful X-ray transient from possible tidal disruption of a white dwarf. https://arxiv.org/abs/2509.25877

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