2024年爆发期间Be/X射线双星SXP 5.05中的星际盘与X射线变异性
Circumstellar Disc and X-ray Variability in the Be/X-ray Binary SXP 5.05 During its 2024 Outburst
- St. Xavier’s College（圣泽维尔学院）
- Tata Institute of Fundamental Research（塔塔基础研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
研究利用多波长分析Be/X射线双星SXP 5.05的2024年爆发，结合X射线和光学观测，分析其光变曲线、光谱演化等，发现此次爆发强度和持续时间降低，支持变异性由盘结构和观测几何变化驱动的观点，该双星是探测Be星盘特性的关键系统。
AI中文摘要：
Be/X射线双星为研究中子星与星际盘之间的相互作用提供了独特机会。SXP 5.05是一个极为罕见的系统，其X射线变异性类似日食，是由Be星盘遮挡而非简单的恒星日食所致。鉴于其特殊几何结构及对2013年爆发的充分研究，我们利用NICER X射线观测和OGLE的长期光学监测对其2024年爆发进行了多波长分析。X射线光变曲线显示此次爆发强度较低、持续时间较短，光谱演化呈现从软、高强度状态到硬、低强度状态的转变。整个观测期间检测到5.05秒附近的相干脉动，光学光变曲线的变化幅度相对于2013年有所减小，轨道相位折叠光学轮廓显示存在持续的、锁相的凹陷结构。这些结果支持观测到的变异性由盘结构和观测几何变化驱动的观点。因此，SXP 5.05仍是通过联合X射线和光学观测探测Be星盘时间相关特性的关键系统。
英文摘要：
Be/X-ray binaries provide a unique opportunity to study the interaction between neutron stars and circumstellar discs. SXP 5.05 is a particularly rare system, exhibiting eclipse-like X-ray variability attributed to obscuration by the Be star disc rather than a simple stellar eclipse. Motivated by its unusual geometry and the well-studied 2013 outburst, we present a multiwavelength analysis of its 2024 outburst using NICER X-ray observations and long-term optical monitoring from OGLE. The X-ray light curve shows a declining outburst with lower peak intensity and shorter duration compared to 2013, indicating a reduced accretion episode. The spectral evolution, characterized through hardness ratios, reveals a transition from a soft, high-intensity state to a harder, low-intensity state. Coherent pulsations near 5.05 s are detected throughout the observations, with properties consistent with previous measurements. The optical light curves show a reduced variability amplitude relative to 2013, possibly from a less extended or less dense circumstellar disc. Orbital-phase-folded optical profiles reveal a persistent, phase-locked dip structure, indicating a stable non-axisymmetric disc component that evolves across outburst phases. Together, these results support a picture in which the observed variability is driven by changes in disc structure and viewing geometry. SXP 5.05 thus remains a key system for probing the time-dependent properties of Be star discs through combined X-ray and optical observations.
