论文标题
瞬态源XTE J1701 $ - $ 462的Kilohertz准周期振荡
Lags of the KiloHertz Quasi-Periodic Oscillations in the transient source XTE J1701$-$462
论文作者
论文摘要
我们分析了Neutron Star X射线X射线二进制XTE J1701 $ - $ 462的Kilohertz准周期振荡（KHz QPO）的14个观察结果，这是第一个在单个爆发过程中表现出清晰过渡和Z样行为之间明确过渡的来源。我们计算了XTE J1701 $ - $ 462在参考/硬带（6.1-25.7 keV）和受试者/软频带（2.1-5.7 keV）之间的XTE J1701 $ - $ 462的平均跨光谱（2.1-5.7 keV），以使用新颖的技术，即khz qpos的平均时间延迟。在环礁阶段，我们发现，在较低kHz qpo的频率下，软光子滞后于$ 18 \ pm 8 $ $ $ $ $，而在z阶段，滞后为$ 33 \ pm35 $ $ $ $ S，与零一致。这两个阶段的滞后差异表明，在XTE J1701 $ -462中，如其他来源所观察到的，滞后随着发光度的增加而降低。我们发现，对于环礁和z相观测，分数RMS幅度随着能量高达$ \ sim $ 10 keV而增加，并且在较高能量下或多或少保持恒定。由于XTE J1701 $ - $ 462的变异性发生的这些变化发生在同一爆发中，因此诸如中子星的质量或系统的倾向之类的属性不对KHz QPO的定时属性的差异负责。在这里，我们建议这些差异是由组成部分或电晕驱动的，可能在耦合模式下与积聚光盘的最内向区域进行振荡。
We analysed 14 observations with kilohertz quasi-periodic oscillations (kHz QPOs) of the neutron star X-ray binary XTE J1701$-$462, the first source to show a clear transition between atoll and Z-like behaviour during a single outburst. We calculated the average cross-spectrum of both atoll and Z-phase observations of XTE J1701$-$462 between a reference/hard band (6.1 - 25.7 keV) and a subject/soft band (2.1 - 5.7 keV) to obtain, using a novel technique, the average time lags of the lower and upper kHz QPOs. During the atoll phase, we found that at the frequency of the lower kHz QPO the soft photons lag behind the hard ones by $18 \pm 8$ $μ$s, whereas during the Z phase the lags are $33\pm35$ $μ$s, consistent with zero. This difference in the lags of both phases suggests that in XTE J1701$-$462, as observed in other sources, the lags decrease with increasing luminosity. We found that for both the atoll and Z phase observations the fractional rms amplitude increases with energy up to $\sim$10 keV and remains more or less constant at higher energies. Since these changes in the variability of XTE J1701$-$462 occur within the same outburst, properties like the mass of the neutron star or the inclination of the system cannot be responsible for the differences in the timing properties of the kHz QPOs in the atoll and Z phase. Here we suggest that these differences are driven by a Comptonizing component or corona, possibly oscillating in a coupled mode with the innermost regions of the accretion disc.
