近日，英国贝尔法斯特女王大学的M. Nicholl及其研究团队取得一项新进展。经过不懈努力，他们发现准周期性的X射线爆发发生在附近潮汐破坏事件数年后。相关研究成果已于2024年10月9日在国际权威学术期刊《自然》上发表。

据悉，准周期爆发（QPEs）是来自星系核心的软X射线明亮爆发，其重复周期为数小时至数周。这些罕见系统的背后机制尚不确定，但大多数理论都涉及围绕超大质量黑洞（SMBHs）的吸积盘发生不稳定性或与近轨道恒星天体相互作用。

有人认为，当超大质量黑洞撕裂一颗经过的恒星时，可能会形成这样的吸积盘，这意味着许多QPE之前应伴有可观测的潮汐撕裂事件（TDEs）。两个已知的QPE源显示出与TDE一致的长期静止光度衰减，而两个观测到的TDE则展现出了与单次爆发一致的X射线耀斑。TDE和QPE也偏好发生在相似的星系中。然而，尚未有确认的重复QPE与通过光谱证实的TDE或在峰值亮度时观测到的光学TDE相关联。

本文报道了从附近一个经过深入研究的光学选择潮汐撕裂事件（TDE）AT2019qiz中探测到的九个X射线准周期爆发（QPEs），其平均复发时间约为48小时。研究人员探测并模拟了来自吸积盘的X射线、紫外线（UV）和光学辐射，并表明一个绕轨天体与该盘的碰撞为QPEs提供了一个合理的解释。

附：英文原文

Title: Quasi-periodic X-ray eruptions years after a nearby tidal disruption event

Author: Nicholl, M., Pasham, D. R., Mummery, A., Guolo, M., Gendreau, K., Dewangan, G. C., Ferrara, E. C., Remillard, R., Bonnerot, C., Chakraborty, J., Hajela, A., Dhillon, V. S., Gillan, A. F., Greenwood, J., Huber, M. E., Janiuk, A., Salvesen, G., van Velzen, S., Aamer, A., Alexander, K. D., Angus, C. R., Arzoumanian, Z., Auchettl, K., Berger, E., de Boer, T., Cendes, Y., Chambers, K. C., Chen, T.-W., Chornock, R., Fulton, M. D., Gao, H., Gillanders, J. H., Gomez, S., Gompertz, B. P., Fabian, A. C., Herman, J., Ingram, A., Kara, E., Laskar, T., Lawrence, A., Lin, C.-C., Lowe, T. B., Magnier, E. A., Margutti, R., McGee, S. L., Minguez, P., Moore, T., Nathan, E., Oates, S. R., Patra, K. C., Ramsden, P., Ravi, V., Ridley, E. J., Sheng, X., Smartt, S. J., Smith, K. W., Srivastav, S., Stein, R., Stevance, H. F., Turner, S. G. D., Wainscoat, R. J., Weston, J., Wevers, T., Young, D. R.

Issue&Volume: 2024-10-09

Abstract: Quasi-periodic eruptions (QPEs) are luminous bursts of soft X-rays from the nuclei of galaxies, repeating on timescales of hours to weeks. The mechanism behind these rare systems is uncertain, but most theories involve accretion disks around supermassive black holes (SMBHs) undergoing instabilities or interacting with a stellar object in a close orbit. It has been suggested that this disk could be created when the SMBH disrupts a passing star, implying that many QPEs should be preceded by observable tidal disruption events (TDEs). Two known QPE sources show long-term decays in quiescent luminosity consistent with TDEs and two observed TDEs have exhibited X-ray flares consistent with individual eruptions. TDEs and QPEs also occur preferentially in similar galaxies. However, no confirmed repeating QPEs have been associated with a spectroscopically confirmed TDE or an optical TDE observed at peak brightness. Here we report the detection of nine X-ray QPEs with a mean recurrence time of approximately 48h from AT2019qiz, a nearby and extensively studied optically selected TDE. We detect and model the X-ray, ultraviolet (UV) and optical emission from the accretion disk and show that an orbiting body colliding with this disk provides a plausible explanation for the QPEs.

DOI: 10.1038/s41586-024-08023-6

Source: https://www.nature.com/articles/s41586-024-08023-6