An Intermediate-mass Black Hole Lurking in A Galactic Halo Caught Alive   during Outburst

C.-C. Jin; D.-Y. Li; N. Jiang; L.-X. Dai; H.-Q. Cheng; J.-Z. Zhu,; C.-W. Yang; A. Rau; P. Baldini; T.-G. Wang; H.-Y. Zhou; W. Yuan; C. Zhang,; X.-W. Shu; R.-F. Shen; Y.-L. Wang; S.-X. Wen; Q.-Y. Wu; Y.-B. Wang; L. L.; Thomsen; Z.-J. Zhang; W.-J. Zhang; A. Coleiro; R. Eyles-Ferris; X. Fang; L.; C. Ho; J.-W. Hu; J.-J. Jin; W.-X. Li; B.-F. Liu; F.-K. Liu; M.-J. Liu; Z.; Liu; Y.-J. Lu; A. Merloni; E.-L. Qiao; R. Saxton; R. Soria; S. Wang; Y.-Q.; Xue; H.-N. Yang; B. Zhang; W.-D. Zhang; Z.-M. Cai; F.-S. Chen; H.-L. Chen,; T.-X. Chen; W. Chen; Y.-H. Chen; Y.-F. Chen; Y. Chen; B. Cordier; C.-Z. Cui,; W.-W. Cui; Y.-F. Dai; H.-C. Ding; D.-W. Fan; Z. Fan; H. Feng; J. A. Garcia,; J. Guan; D.-W. Han; D.-J. Hou; H.-B. Hu; M.-H. Huang; J. Huo; S.-M. Jia,; Z.-Q. Jia; B.-W. Jiang; G. Jin; X. Kong; E. Kuulkers; W.-H. Lei; C.-K. Li,; J.-F. Li; L.-H. Li; M.-S. Li; W. Li; Z.-D. Li; T.-Y. Lian; Z.-X. Ling; C.-Z.; Liu; H.-Y Liu; H.-Q. Liu; J.-F. Liu; Y. Liu; F.-J. Lu; L.-D. Luo; J. Ma; X.; Mao; H.-Y. Mu; K. Nandra; P. O'Brien; H.-W. Pan; X. Pan; G.-J. Qin; N. Rea,; J. Sanders; L.-M. Song; H. Sun; S.-L. Sun; X.-J. Sun; Y.-Y. Tan; Q.-J. Tang,; Y.-H. Tao; B.-C. Wang; J. Wang; J.-F. Wang; L. Wang; W.-X. Wang; Y.-S. Wang,; Z.-X. Wang; Q.-W. Wu; X.-F. Wu; H.-T. Xu; J.-J. Xu; X.-P. Xu; Y.-F. Xu; Z.; Xu; C.-B. Xue; S.-J. Xue; Y.-L. Xue; A.-L. Yan; X.-T. Yang; Y.-J. Yang; J.; Zhang; M. Zhang; S.-N. Zhang; Y.-H. Zhang; Z. Zhang; Z. Zhang; Z.-L. Zhang,; D.-H. Zhao; H.-S. Zhao; X.-F. Zhao; Z.-J. Zhao; J. Zheng; Q.-F. Zhu; Y.-X.; Zhu; Z.-C. Zhu; H. Zou

arXiv:2501.09580·astro-ph.HE·January 17, 2025

An Intermediate-mass Black Hole Lurking in A Galactic Halo Caught Alive during Outburst

C.-C. Jin, D.-Y. Li, N. Jiang, L.-X. Dai, H.-Q. Cheng, J.-Z. Zhu,, C.-W. Yang, A. Rau, P. Baldini, T.-G. Wang, H.-Y. Zhou, W. Yuan, C. Zhang,, X.-W. Shu, R.-F. Shen, Y.-L. Wang, S.-X. Wen, Q.-Y. Wu, Y.-B. Wang, L. L., Thomsen, Z.-J. Zhang, W.-J. Zhang, A. Coleiro

PDF

TL;DR

This paper reports the first confirmed off-nucleus intermediate-mass black hole tidal disruption event, discovered through real-time X-ray and optical observations, highlighting the power of time-domain surveys in studying IMBHs.

Contribution

It provides the first unambiguous detection of an IMBH in a galactic halo actively disrupting a star, demonstrating the effectiveness of combined X-ray and optical follow-ups.

Findings

01

Confirmed off-nucleus IMBH tidal disruption event

02

Demonstrated the utility of time-domain X-ray surveys

03

Provided insights into IMBH environments and origins

Abstract

Stellar-mass and supermassive black holes abound in the Universe, whereas intermediate-mass black holes (IMBHs) of ~10^2-10^5 solar masses in between are largely missing observationally, with few cases found only. Here we report the real-time discovery of a long-duration X-ray transient, EP240222a, accompanied by an optical flare with prominent H and He emission lines revealed by prompt follow-up observations. Its observed properties evidence an IMBH located unambiguously in the halo of a nearby galaxy and flaring by tidally disrupting a star -- the only confirmed off-nucleus IMBH-tidal disruption event so far. This work demonstrates the potential of sensitive time-domain X-ray surveys, complemented by timely multi-wavelength follow-ups, in probing IMBHs, their environments, demographics, origins and connections to stellar-mass and supermassive black holes.

Peer Reviews

No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.

Videos

No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.