论文标题
模糊的X射线二进制文件V404 CYG,CYG X-3,V4641 SGR和GRS 1915+105
The obscured X-ray binaries V404 Cyg, Cyg X-3, V4641 Sgr, and GRS 1915+105
论文作者
论文摘要
V404 CYG,CYG X-3,V4641 SGR和GRS 1915+105是最亮的X射线二进制文件之一,并在其多波长发射中显示出复杂的行为。除了CYG X-3外,其他三个来源具有大的积聚磁盘,并且有高轨道倾斜度的证据。因此,积聚磁盘的任何大规模几何变化都可能导致局部遮挡事件。另一方面,Cyg X-3在巨大的恒星风中绕其狼射线伴侣星绕,遮盖了X射线源。我们在这里研究是否可以通过局部掩饰事件来解释所有四个来源观察到的奇特X射线光谱。我们将源光谱与两个有力动机的模型拟合,描述了一个场景,其中所有内在发射都在周围的问题中重新加工,或者发射极被带有可变开头的厚圆环包围。我们表明,特定时间期间的X射线光谱在所有四个来源中都相似,这可能是由于它们嵌入的高密度环境而产生的。拟合的模型表明,在2015年V404 CYG爆发中发生强烈耀斑的发作之前的低亮度阶段被严重遮盖,但本质上非常明亮(超级埃德丁顿)增生状态。从最近的,异常低的亮度状态1915+105中观察到与V404 CYG相似的光谱演变。建模结果表明,V404 CYG和GRS 1915+105中(流出的)遮盖物的几何变化,这也与无线电(JET)演化有关。所有来源都显示出模糊的X射线发射,但具有不同的固有亮度,指向导致晦涩的不同因素。这项工作突出了考虑在其他来源中可能发生的X射线光谱的建模中,考虑到周围介质中X射线发射的重新处理的重要性。
V404 Cyg, Cyg X-3, V4641 Sgr, and GRS 1915+105 are among the brightest X-ray binaries and display complex behavior in their multiwavelength emission. Apart from Cyg X-3, the other three sources have large accretion disks, and there is evidence of a high orbital inclination. Therefore, any large scale geometrical change in the accretion disk can cause local obscuration events. On the other hand, Cyg X-3 orbits its Wolf-Rayet companion star inside the heavy stellar wind obscuring the X-ray source. We study here whether the peculiar X-ray spectra observed from all four sources can be explained by local obscuration events. We fit the source spectra with two physically motivated models describing either a scenario where all the intrinsic emission is reprocessed in the surrounding matter or where the emitter is surrounded by a thick torus with variable opening angle. We show that the X-ray spectra during specific times are similar in all four sources likely arising from the high-density environments where they are embedded. The fitted models suggest that a low-luminosity phase preceding an intense flaring episode in the 2015 outburst of V404 Cyg is heavily obscured, but intrinsically very bright (super-Eddington) accretion state. Similar spectral evolution to that of V404 Cyg is observed from the recent, unusually low-luminosity state of GRS 1915+105. The modeling results point to a geometry change in the (outflowing) obscuring matter in V404 Cyg and GRS 1915+105, which is also linked to the radio (jet) evolution. All sources display obscured X-ray emission but with different intrinsic luminosities which points towards different factors causing the obscuration. This work highlights the importance of taking into account the reprocessing of the X-ray emission in the surrounding medium in the modeling of the X-ray spectra that may well take place in other sources as well.