1. An Intermediate-mass Black Hole Lurking in A Galactic Halo Caught Alive during Outburst
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Jin, C. -C., Li, D. -Y., Jiang, N., Dai, L. -X., Cheng, H. -Q., Zhu, J. -Z., Yang, C. -W., Rau, A., Baldini, P., Wang, T. -G., Zhou, H. -Y., Yuan, W., Zhang, C., Shu, X. -W., Shen, R. -F., Wang, Y. -L., Wen, S. -X., Wu, Q. -Y., Wang, Y. -B., Thomsen, L. L., Zhang, Z. -J., Zhang, W. -J., Coleiro, A., Eyles-Ferris, R., Fang, X., Ho, L. C., Hu, J. -W., Jin, J. -J., Li, W. -X., Liu, B. -F., Liu, F. -K., Liu, M. -J., Liu, Z., Lu, Y. -J., Merloni, A., Qiao, E. -L., Saxton, R., Soria, R., Wang, S., Xue, Y. -Q., Yang, H. -N., Zhang, B., Zhang, W. -D., Cai, Z. -M., Chen, F. -S., Chen, H. -L., Chen, T. -X., Chen, W., Chen, Y. -H., Chen, Y. -F., Chen, Y., Cordier, B., Cui, C. -Z., Cui, W. -W., Dai, Y. -F., Ding, H. -C., Fan, D. -W., Fan, Z., Feng, H., Garcia, J. A., Guan, J., Han, D. -W., Hou, D. -J., Hu, H. -B., Huang, M. -H., Huo, J., Jia, S. -M., Jia, Z. -Q., Jiang, B. -W., Jin, G., Kong, X., Kuulkers, E., Lei, W. -H., Li, C. -K., Li, J. -F., Li, L. -H., Li, M. -S., Li, W., Li, Z. -D., Lian, T. -Y., Ling, Z. -X., Liu, C. -Z., Liu, H. -Y, Liu, H. -Q., Liu, J. -F., Liu, Y., Lu, F. -J., Luo, L. -D., Ma, J., Mao, X., Mu, H. -Y., Nandra, K., O'Brien, P., Pan, H. -W., Pan, X., Qin, G. -J., Rea, N., Sanders, J., Song, L. -M., Sun, H., Sun, S. -L., Sun, X. -J., Tan, Y. -Y., Tang, Q. -J., Tao, Y. -H., Wang, B. -C., Wang, J., Wang, J. -F., Wang, L., Wang, W. -X., Wang, Y. -S., Wang, Z. -X., Wu, Q. -W., Wu, X. -F., Xu, H. -T., Xu, J. -J., Xu, X. -P., Xu, Y. -F., Xu, Z., Xue, C. -B., Xue, S. -J., Xue, Y. -L., Yan, A. -L., Yang, X. -T., Yang, Y. -J., Zhang, J., Zhang, M., Zhang, S. -N., Zhang, Y. -H., Zhang, Z., Zhang, Z. -L., Zhao, D. -H., Zhao, H. -S., Zhao, X. -F., Zhao, Z. -J., Zheng, J., Zhu, Q. -F., Zhu, Y. -X., Zhu, Z. -C., and Zou, H.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Astrophysics of Galaxies - 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., Comment: 64 pages, 15 figures, submitted
- Published
- 2025