标题： 吸积黑洞Swift J1727.8-1613中准周期振荡的时域演化：状态转换期间盘-冕的共同演化 显示英文标题

标题： Temporal evolution of quasi-periodic oscillations in an accreting black hole Swift J1727.8-1613: coevolution of the disk-corona during the state transition

摘要： 低频准周期振荡（QPOs）在黑洞X射线双星中经常被观测到，其频率已被发现与各种能量光谱特性相关。 在本研究中，我们对Swift J1727.8-1613进行了详细的时域分析，揭示了QPO频率与观测到的吸积盘辐射之间的一种新型双分支相关性，这与之前发现的单一相关性不同。 具体而言，在QPO频率低于3 Hz时，QPO频率与观测到的吸积盘辐射呈负相关。 当QPO频率超过约3 Hz时，这种负相关关系会转变为正相关。 QPO频率与康普顿通量之间的相关性呈现出相反的趋势，在较低频率时呈正相关，在较高频率时呈负相关。 我们将这些行为解释为在Lense-Thirring进动热流框架下，吸积盘-日冕几何结构演变的特征。 此外，我们发现，在爆发状态下，QPO的分数均方根（rms）在15 keV以上几乎保持不变，但在该阈值以下随能量增加而增加。 随着能量光谱变软，rms-能量关系的斜率变得更为陡峭。 显示英文摘要

摘要： Low-frequency quasi-periodic oscillations (QPOs) are commonly observed in black hole X-ray binaries, and their frequency has been found to correlate with various energy spectral properties. In this work, we present a detailed timing analysis of Swift J1727.8-1613, revealing a novel two-branch correlation between the QPO frequency and the observed disk emission, which differs from previous findings of a single correlation. Specifically, at QPO frequencies below 3 Hz, the QPO frequency is negatively correlated with the observed disk emission. Such a negative relation transitions to a positive one, as the QPO frequency exceeds approximately 3 Hz. The correlation between QPO frequency and Compton flux exhibits an opposite trend, with a positive correlation at lower frequencies and a negative correlation at higher ones. We interpret these behaviors as signatures of an evolving disk-corona geometry, within the framework of a Lense-Thirring precessing hot flow. Additionally, we find that during the flare state, the QPO fractional root-mean-square (rms) remains nearly constant above 15 keV, but increases with energy below this threshold. The slope of the rms-energy relation becomes steeper as the energy spectrum softens.