AI 中文总结
本研究利用 TESS 数据，通过两种方法首次在 BL Lac 天体 RX J0805.4+7534 的光变曲线中检测到日间 QPO，提出其可能由相对论性喷流扭结不稳定性导致。
AI 中文摘要
本文首次报告在 BL Lac 天体 RX J0805.4+7534 的光变曲线中检测到准周期振荡（QPO）。凌日系外行星勘测卫星（TESS）在7个天区扇区观测了该源，我们采用定制方法提取了这些扇区的光变曲线，在这些光变曲线中发现了 QPO 信号的存在。为检测周期性并评估 QPO 信号的统计显著性，我们使用了两种方法：Lomb-Scargle 周期图和加权小波 Z 变换，两种不同方法得出了一致结果。结果表明，扇区20、26和53中存在 QPO 信号，置信水平超过99.73%，扇区20和26的 QPO 周期约为3.8天，全局显著性为95%。为解释这些快速准周期变化，我们讨论了几种可能的物理场景，最可能的是相对论性喷流中的扭结不稳定性，另一种可能是最内侧吸积盘中热点的旋转。基于热点轨道模型假设，估算了该 BL Lac 天体中心黑洞的质量。这两种解释的有效性需要进一步观测数据验证，但由于 BL Lac 天体的辐射主要源自喷流，我们更倾向于相对论性喷流中的扭结不稳定性是这种快速 QPO 的成因。
英文摘要
This paper reports for the first time the detection of quasi-periodic oscillations (QPOs) in the light curves of the BL Lacertae object RX J0805.4+7534. The Transiting Exoplanetary Survey Satellite (TESS) observed this source in seven sectors of the sky, and we extracted the light curves for these sectors using a custom method. The presence of QPO signals was found in these light curves. To detecte the periodicity and assess the statistical significance of the QPO signals, we employed two methods: Lomb-Scargle periodograms and Weighted Wavelet \textit{Z}-transform. Both of these different methods yielded consistent results. \textcolor{red}{\sout{The results showed signals with day-timescale QPO in sectors 20, 26, 53, and 73, with confidence levels exceeding $3σ$, and three of the sectors exhibited a ~3.8 days QPO. To explain these rapid quasi-periodic changes, we discuss several possible explanations. We propose that the QPO signal might be due to the rotation of hot spots on circular orbits within the accretion disk.}}\textcolor{blue}{The results show that QPO signals exist in sectors 20, 26, and 53, with the confidence levels exceeding 99.73\%. The QPOs in sectors 20 and 26 are $\sim 3.8$ days and have a global significance of 95\%. To explain these rapid quasi-periodic variations, we discussed several possible physical scenarios. The most possible one is the kink instability in relativistic jets. The other possible scenario is the rotation of hot-spots in the innermost accretion disk. Based on the hot-spot orbital model hypothesis, the mass of the black hole at the center of this BL Lac object wes estimated. The validity of these two explanations requires further observational data to verify. However, since the radiation of BL Lac objects primarily originates from jets, we prefer the kink instability in relativistic jets to be the cause of this rapid QPO.
Comments13 pages, 4 figures. accepted for publication in RAA
