AI 中文总结
该研究通过NICER观测暂现X射线脉冲星4U 0115+63的宁静态转变，发现热-粘滞吸积盘不稳定性模型可解释其行为，无需推进效应作为转变的主要机制。
AI 中文摘要
暂现X射线脉冲星（XRP）爆发的最终阶段以吸积率显著下降为特征，为研究吸积盘物理及其与中子星（NS）强磁场的相互作用提供了宝贵线索。其中，“推进效应”（即离心力对吸积的抑制）被认为是决定爆发光度及快速转变为宁静态时标的的关键机制，还可作为估算NS磁场强度的独立方法。另一方面，吸积率本身的降低由远离NS的吸积流中的过程驱动。因此，要从光变曲线中提取相关信息，需要高灵敏度、高时间分辨率的X射线监测，以捕捉从吸积态到宁静态的快速且往往不可预测的转变过程。本研究利用NICER X射线望远镜的观测结果，开展了首个针对暂现XRP 4U 0115+63向宁静态转变全过程的综合监测。研究表明，观测到的行为可由热-粘滞吸积盘不稳定性模型（DIM）解释：爆发后立即观测到的辐射可能来自重组合的“冷”吸积盘的持续吸积，而后续的宁静态辐射则由冷却的NS产生。我们进一步将该模型应用于包含广泛物理参数的更大样本XRP。最终，研究结果表明，XRP的时间行为（包括宁静态）可在DIM框架内得到一致解释，无需将推进效应作为观测到的转变的主要机制。
英文摘要
The final stages of outbursts in transient X-ray pulsars (XRPs), which are characterised by a significant decline in the mass accretion rate, provide valuable insight into the physics of the accretion disc and its interaction with the strong magnetic field of the neutron star (NS). In particular, the `propeller effect', or centrifugal inhibition of accretion, has been proposed as a key mechanism governing both the onset luminosity and the timescale of the rapid transition to the quiescent state. In addition, it offers an independent method for estimating the magnetic field strength of the NS. On the other hand, the decrease in the mass accretion rate itself is driven by processes occurring in the accretion flow at larger distances from the NS. Recovering the information encoded in the light curve therefore requires sensitive high-cadence X-ray monitoring capable of capturing the rapid and often unpredictable transition from the accreting regime to the quiescent regime. In this study, we present the results of the first comprehensive monitoring campaign that tracks the entire transition to quiescence in the transient XRP 4U 0115+63 utilising observations by the NICER X-ray telescope. We show that the observed behaviour can be explained by the thermal-viscous disc instability model (DIM), with the emission observed immediately after an outburst possibly arising from the ongoing accretion from the recombined (`cold') disc and the subsequent quiescent emission being produced by the cooling NS. We further applied this model to a larger sample of XRPs encompassing a broad range of physical parameters. Ultimately, our findings indicate that the temporal behaviour of XRPs, including the quiescent state, can be consistently explained within the DIM framework without requiring the propeller effect as the primary mechanism governing the observed transition.
Comments11 pages, 5 figures, A&A, in press
