论文标题
$ \ sim $ \ sim $ 40 MHz在CEN X-3中检测准周期性振荡与Insight-HXMT
Detection of a quasi-periodic oscillation at $\sim$40 mHz in Cen X-3 with Insight-HXMT
论文作者
论文摘要
我们研究了通过Insight-HXMT观察到的增生驱动X射线脉冲星CEN X-3中的准周期振荡（QPO）特征。对于2020年CEN X-3处于极柔软状态时的两个观察结果，功率密度谱显示出明显的QPO特征，$ \ sim $ 40 MHz，平均分数RMS幅度为$ \ sim9 \％$。我们研究了轨道阶段的MHz QPO频率和RMS振幅，发现QPO频率为$ \ sim $ \ sim $ 33-39 MHz在0.1-0.4的轨道阶段，在0.4-0.8的轨道阶段，轨道上的$ 37-43 MHz增加到$ 37-43 MHz，但在x-ray inne no the x-ray ins the x-ray Intentive no no no the x-ray Intentive in no n no the Intence。我们还进行了依赖能量的QPO分析，随着能量从2个KEV增加到20个KEV，MHz QPO的RMS幅度具有下降的趋势。此外，QPO时差分析表明，时间延迟为$ \ sim 20 $ 20 $ MS（硬滞后）在$ \ sim $ 5-10 keV范围内，并且在$ \ sim 10 $ kev上变为负（$ - （20-70）$ MS）。总结和讨论了不同的QPO理论模型。最后，我们建议当CEN X-3中MHz QPO的原始定时特征以及CEN X-3中的MHz QPO的起源可能归因于在旋转半径附近截断积聚磁盘时的不稳定。
We investigated the quasi-periodic oscillation (QPO) features in the accretion-powered X-ray pulsar Cen X-3 observed by Insight-HXMT. For two observations in 2020 when Cen X-3 was in an extremely soft state, the power density spectrum revealed the presence of obvious QPO features at $\sim$40 mHz with an averaged fractional rms amplitude of $\sim9\%$. We study the mHz QPO frequency and rms amplitude over orbital phases, and find that the QPO frequency is $\sim$33-39 mHz at the orbital phase of 0.1-0.4, increasing to $\sim$37-43 mHz in the orbital phase of 0.4-0.8, but has no strong dependence on X-ray intensity. We also carried out an energy-dependent QPO analysis, the rms amplitude of the mHz QPOs have a decreasing trend as the energy increases from 2 to 20 keV. In addition, the QPO time-lag analysis shows that the time delay is $\sim 20$ ms (a hard lag) in the range of $\sim$5-10 keV, and becomes negative (time lag of $-(20-70)$ ms) above $\sim 10$ keV. The different QPO theoretical models are summarized and discussed. In the end, we suggest that these energy-dependent timing features as well as the origin of mHz QPOs in Cen X-3 may be ascribed to an instability when the accretion disk is truncated near the corotation radius.
