Radiation hydrodynanmic simulations of a super-Eddington accretor as a model for ultra-luinous sources
Radiation hydrodynanmic simulations of a super-Eddington accretor as a model for ultra-luinous sources
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超级爱丁顿吸积体作为超发光源模型的辐射流体动力学模拟
DOI：
10.1093/pasj/psx006
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发表时间：
2017
影响因子：
2.3
通讯作者：
K.
中科院分区：
文献类型：
--
作者：
Ogawa;T.;Mineshige;S.;Kawashima;T.;Ohsuga;K.;Hashizume;K.
我们对超爱丁顿吸积流和伴随的流出流进行了二维辐射流体动力学（RHD）模拟，以研究如何从不同的观测方向观察到它们。我们考虑在质量注入速率为$\skew4\dot{M}_{\rm inj}/{\skew4\dot{M}_{\rm Edd}}=10^{2}$， 103和104（单位分别为，ledandc分别为爱丁顿光度和光速）的情况下，黑洞周围的气体动力学和辐射传递，并考虑逆康普顿散射。我们证实了这样一种趋势，即质量吸积率越高，流出量相对于吸积流量的相对重要性就越大。观测到的超级爱丁顿流的外观是不同的，这取决于是从边缘方向还是从正面方向观察。这是因为近边缘的观察者只能看到内部垂直膨胀部分的外部，较冷的（~ 106K）表面。简要讨论了超亮x射线源（ULXs）、极亮x射线源（E-ULXs）和超亮超软源（ULSs）的观测特性。我们发现E-ULXs的极高亮度（L ~ 1041ergs−1）可以解释为当从近正方向观测到以非常高的吸积速率流向黑洞（> 20M⊙）。如果从大视角（θ≥30°）观察- 103的超爱丁顿流，就可以解释在超光速黑洞中观测到的高亮度（~ 1039erg s−1）和非常柔软的黑体样光谱（温度约为0.1 keV）。
We perform two-dimensional radiation hydrodynamic (RHD) simulations of super-Eddington accretion flow and the accompanying outflow to investigate how they will be observed from various viewing directions. We consider gas flow around a 10M⊙black hole for mass injection rates of $\skew4\dot{M}_{\rm inj}/{\skew4\dot{M}_{\rm Edd}}=10^{2}$, 103, and 104(in units of, withLEddandcbeing the Eddington luminosity and the speed of light, respectively), and solve gas dynamics and radiation transfer around the black hole, taking into account inverse Compton scattering. We confirm the tendency that the higher the mass accretion rate is, the larger the relative importance of outflow over accretion flow becomes. The observational appearance of the super-Eddington flow is distinct, depending on whether it is viewed from the edge-on direction or from the face-on direction. This is because nearly edge-on observers can only see the outer, cooler (∼106K) surface of the inner, vertically inflated part of the flow. Observational properties are briefly discussed in the context of the ultra-luminous X-ray sources (ULXs), the extreme ULXs (E-ULXs), and the ultra-luminous supersoft sources (ULSs). We find that the extremely high luminosities of E-ULXs (L∼ 1041erg s−1) can be explained when the flow on to the black hole with ≳20M⊙with a very high accretion rate,, is observed from the nearly face-on direction. The high luminosity (∼1039erg s−1) and the very soft blackbody-like spectra with temperatures around 0.1 keV, which are observed in the ULSs, can be explained if the super-Eddington flow with–103is viewed from large viewing angles, θ ≳ 30°.