发表机构
Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías, Universidad de Alicante; Sternberg Astronomical Institute, Moscow M.V. Lomonosov State University; Institute for Physics and Astronomy, Universität Potsdam（阿利坎特大学应用物理科学与技术大学研究所; 莫斯科罗蒙诺索夫国立大学斯特恩伯格天文研究所; 波茨坦大学物理与天文学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过对比2015与2025年XMM-Newton观测，发现4U 0114+65光度下降约一个数量级，提出其可能首次进入强耦合机制下的部分离心抑制状态，导致吸积效率降低而非自转调制丧失。
AI 中文摘要
4U 0114+65 是一个高质量 X 射线双星系统，由 B1 Ia 超巨星 V* V662 Cas 和已知最慢的吸积中子星之一组成，其自转周期约为 9.4 ks。2025 年，其长周期 X 射线脉动在《Swift》/BAT 监测中变得无法探测，促使我们利用《XMM-Newton》进行了一次主任酌情时间观测。我们将此次观测与 2015 年《XMM-Newton》观测（当时源更亮且脉动清晰）进行比较，并利用《Swift》/BAT 数据分析其长期自转演化。我们采用与先前工作相同的模型进行了平均谱和脉冲相位分辨谱分析。2025 年的观测仍揭示了微弱的脉动，周期约为 9.3 ks，尽管在《Swift》/BAT 中未探测到。两个时期的整体光谱形状保持相似，但光度下降了约一个数量级，主要归因于体运动康普顿化分量的强烈抑制。尽管 2025 年的吸收柱密度更高，但推断出的风性质与 2015 年的结果大致兼容，表明供体风无需发生重大全局变化。相反，结果指向中子星磁层附近吸积效率的显著降低。我们提出，4U 0114+65 可能正在向强耦合机制下的部分离心抑制演化，其中环向磁场分量与极向分量相当。如果得到证实，这将是该状态的首个观测证据。吸积将逐渐变得效率更低且更间歇性，而不会达到完全发展的螺旋桨机制。长期硬 X 射线监测中脉动的表观消失，则源于较低的光度和减少的绝对脉冲通量，而非底层自转调制的丧失。
英文摘要
4U~0114+65 is a high-mass X-ray binary composed of the B1\,Ia supergiant V*~V662~Cas and one of the slowest known accreting neutron stars, with a spin period of $\sim$9.4 ks. In 2025, its long X-ray pulsations became undetectable in \textit{Swift}/BAT monitoring, motivating a Director's Discretionary Time observation with \textit{XMM-Newton}. We compare this observation with a 2015 \textit{XMM-Newton} observation, when the source was brighter and clearly pulsed, and analyze the long-term spin evolution using \textit{Swift}/BAT data. We performed average and pulse-phase-resolved spectroscopy using the same model as in previous work. The 2025 observation still reveals weak pulsations, with a period of about 9.3 ks, despite their non-detection in \textit{Swift}/BAT. The overall spectral shape remains similar in both epochs, but the luminosity decreased by about one order of magnitude, mainly due to strong suppression of the bulk-motion Comptonization component. Although the absorbing column is higher in 2025, the inferred wind properties remain broadly compatible with those from 2015, suggesting that no major global change in the donor wind is required. Instead, the results point to a substantial reduction in accretion efficiency close to the neutron-star magnetosphere. We propose that 4U~0114+65 may be evolving toward partial centrifugal inhibition in the strong-coupling regime, where the toroidal magnetic-field component is comparable to the poloidal one. If confirmed, this would represent the first observational evidence of this state. Accretion would become progressively less efficient and more intermittent without reaching a fully developed propeller regime. The apparent disappearance of the pulse in long-term hard X-ray monitoring would then result from the lower luminosity and reduced absolute pulsed flux, rather than from the loss of the underlying spin modulation.
