论文标题
是什么决定了超级 - 埃德丁顿的独特光谱？
What Determines Unique Spectra of Super-Eddington Accretors?: Origin of Optically Thick and Low Temperature Coronae in Super-Eddington Accretion Flows
论文作者
论文摘要
Existence of relatively cool ($k_B T \lesssim 10~{\rm keV}$) and optically thick ($τ\gtrsim 3$) coronae are inferred above super-Eddington accretion flow such as ultraluminous X-ray sources (ULXs), GRS 1915+105, and narrow-line Seyfert 1 galaxies (NLS1), which contrasts the cases in sub-eDdington积聚流，与冠冕与$ k_b t \ sim 100〜 {\ rm kev} $和$τ\ sim 1 $相关。为了了解它们的物理起源，我们研究了电晕的发射特性，该发射特性是由辐射压力从超级 - 埃德丁顿内盘吹出的气体形成的。我们假设电晕是通过从下面磁盘中出现的磁环的重新连接而加热的。我们表明，这种辐射压力驱动的风可以充当光学厚的电晕，从而将基础磁盘的热柔软光子进行对抗，并且使用合理的参数集，我们可以从理论上重现冠状光学深度和温度，并通过观测数据的光谱仪来推断。相比之下，在亚埃丁顿案例中，冠状光学深度不能如此之高，因为冠状材料是通过蒸发从磁盘提供的，并且蒸发率最大限制。我们支持低温，光学厚的构成应该是超级 - 埃德丁顿积聚流量的关键特征。
Existence of relatively cool ($k_B T \lesssim 10~{\rm keV}$) and optically thick ($τ\gtrsim 3$) coronae are inferred above super-Eddington accretion flow such as ultraluminous X-ray sources (ULXs), GRS 1915+105, and narrow-line Seyfert 1 galaxies (NLS1), which contrasts the cases in sub-Eddington accretion flows, which are associated with coronae with $k_B T \sim 100~{\rm keV}$ and $τ\sim 1$. To understand their physical origin, we investigate the emission properties of the corona which is formed by the gas blown off the super-Eddington inner disk by radiation pressure. We assume that the corona is heated by the reconnection of magnetic loops emerged from the underlying disk. We show that this radiation pressure driven wind can act as an optically thick corona which upscatters thermal soft photons from the underlying disk, and that with a reasonable parameter set we can theoretically reproduce the coronal optical depth and temperature which are inferred by spectral fittings of observational data. By contrast, the coronal optical depth cannot be so high in sub-Eddington cases, since the coronal material is supplied from the disk via evaporation and there is a maximum limit on the evaporation rate. We support that the low temperature, optically thick Comptonization should be a key signature of super-Eddington accretion flow.
