Ultrafast outflows in ultraluminous X-ray sources
Ultrafast outflows in ultraluminous X-ray sources
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DOI：
10.1002/asna.201713336
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发表时间：
2016-11
期刊：
影响因子：
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通讯作者：
C. Pinto;A. Fabian;M. Middleton;D. Walton
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文献类型：
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作者：
C. Pinto;A. Fabian;M. Middleton;D. Walton
超铝X射线源（ULX）是明亮的河外源，X射线光度超过10^39 erg/s，由致密天体吸积提供动力。根据第一次使用XMM-牛顿进行的研究，ULX似乎是中等质量黑洞（10^2-4太阳质量）的绝佳候选者。然而，在过去的几年里，对大多数ULX的恒星质量黑洞或中子星上的超级爱丁顿吸积的解释已经获得了强烈的共识。确认超级爱丁顿情景的一个关键缺失部分是直接检测到大规模的辐射驱动风，预计这些风是ULX光谱中的原子发射/吸收线。风的第一个证据是在ULX的软X射线光谱中发现的。最近，我们已经能够解决这些残差到静止帧发射和蓝移（~0.2c）吸收线所产生的高度电离的气体在深高分辨率XMM-牛顿光谱的两个超铝X射线源。因此，紧凑的物体被强大的超快风包围，正如超爱丁顿吸积模型所预测的那样。在这里，我们将讨论这些发现的相关性，以及在许多其他超亮X射线源中对强风进行深入的XMM-牛顿观测的重要性，以估计风的能量、系统的几何形状和中央吸积体的质量。
Ultraluminous X-ray sources (ULXs) are bright extragalactic sources with X-ray luminosities above 10^39 erg/s powered by accretion onto compact objects. According to the first studies performed with XMM-Newton ULXs seemed to be excellent candidates to host intermediate-mass black holes (10^2-4 solar masses). However, in the last years the interpretation of super-Eddington accretion onto stellar-mass black holes or neutron stars for most ULXs has gained a strong consensus. One critical missing piece to confirm the super-Eddington scenario was the direct detection of the massive, radiatively-driven winds expected as atomic emission/absorption lines in ULX spectra. The first evidence for winds was found as residuals in the soft X-ray spectra of ULXs. Most recently we have been able to resolve these residuals into rest-frame emission and blueshifted (~0.2c) absorption lines arising from highly ionized gas in the deep high-resolution XMM-Newton spectra of two ultraluminous X-ray sources. The compact object is therefore surrounded by powerful ultrafast winds as predicted by models of hyper-Eddington accretion. Here we discuss the relevance of these discoveries and the importance of further, deep, XMM-Newton observations of powerful winds in many other ultraluminous X-ray sources to estimate the energetics of the wind, the geometry of the system, and the masses of the central accretors.