An ionized accretion disc wind in Hercules X-1
An ionized accretion disc wind in Hercules X-1
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DOI：
10.1093/mnras/stz3200
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发表时间：
2019-10
影响因子：
4.8
通讯作者：
P. Kosec;A. Fabian;Ciro Pinto;D. Walton;S. Dyda;C. Reynolds
中科院分区：
文献类型：
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作者：
P. Kosec;A. Fabian;Ciro Pinto;D. Walton;S. Dyda;C. Reynolds
武仙座X-1是研究得最好的高磁化中子星星X射线双星之一，拥有丰富的档案数据。我们目前的发现，电离风的X射线谱时，源是在高的状态。在大多数XMM-牛顿观测中，风的探测在统计上是显著的，速度范围从200到1000 km s-1。观测到的铁K波段的特征可以用风的吸收和铁发射线的森林来解释。然而，我们也检测到氮，氧和氖吸收线在相同的系统速度在高分辨率反射光栅光谱仪光栅光谱。风必须从吸积盘发射，并且可能是在可比速度下观察到的紫外线吸收特征的祖先，但后者可能起源于距离致密物体远得多的距离。我们发现流出物质的电离水平和电离光度以及超轨道相位之间有很强的相关性。如果光度驱动了相关性，那么风可能是由康普顿加热和辐射压力的组合发射的。相反，如果超轨道相位是变化的驱动因素，那么观测结果可能会扫描弯曲吸积盘上方不同高度的风。如果是这样的话，我们可以估计出风的质量流出率，修正为有限的发射立体角，大约是质量吸积率的70%。
Hercules X-1 is one of the best-studied highly magnetized neutron star X-ray binaries with a wealth of archival data. We present the discovery of an ionized wind in its X-ray spectrum when the source is in the high state. The wind detection is statistically significant in most of the XMM–Newton observations, with velocities ranging from 200 to 1000 km s−1. Observed features in the iron K band can be explained by both wind absorption and a forest of iron emission lines. However, we also detect nitrogen, oxygen, and neon absorption lines at the same systematic velocity in the high-resolution Reflection Grating Spectrometer grating spectra. The wind must be launched from the accretion disc, and could be the progenitor of the ultraviolet absorption features observed at comparable velocities, but the latter likely originate at significantly larger distances from the compact object. We find strong correlations between the ionization level of the outflowing material and the ionizing luminosity as well as the superorbital phase. If the luminosity is driving the correlation, the wind could be launched by a combination of Compton heating and radiation pressure. If instead the superorbital phase is the driver for the variations, the observations are likely scanning the wind at different heights above the warped accretion disc. If this is the case, we can estimate the wind mass outflow rate, corrected for the limited launching solid angle, to be roughly 70 per cent of the mass accretion rate.