Radiative efficiency of hot accretion flows
Radiative efficiency of hot accretion flows
复制标题
热吸积流的辐射效率
DOI：
10.1111/j.1365-2966.2012.22030.x
复制
发表时间：
2012-07
影响因子：
4.8
通讯作者：
Yuan, Feng
中科院分区：
文献类型：
--
作者：
Xie, Fu-Guo;Yuan, Feng
在过去的几年里，我们对热吸积流的理解已经通过两个发现得到了显着的改善：（i）只有一小部分在外边界处可用的吸积流最终可以落在黑洞上，而大部分都在外流中丢失了;（ii）电子可以直接接收吸积流中粘性耗散能量的大部分（i）。e.δ类似于0.1-0.5）。当考虑这两个发现时，热吸积流的辐射效率尚未得到系统的研究，这是我们论文的主题。我们考虑热吸积模型的两个区域：平流主导的吸积流，位于低吸积率的区域，小于或接近10 α L-2（Edd）/c（2），和发光的热吸积流（LHAF），位于该吸积率以上。对于LHAF，我们假设吸积流在一定的吸积率以上具有两相结构，并且我们在动力学计算中采用了简化。我们的结果表明，热吸积流的辐射效率随着吸积率的增加而增加，并且与之前的delta << 1的情况相比，对电子的直接粘性加热大大增强了热吸积流的辐射效率。当吸积率高时，热吸积流的辐射效率与标准薄盘的辐射效率相当。我们提出了拟合公式的辐射效率作为吸积率的函数的各种值的三角洲。
Over the past few years, our understanding of hot accretion flows has been improved significantly by two findings: (i) only a small fraction of the accretion flow available at the outer boundary can finally fall on to the black hole, while most of it is lost in the outflow; (ii) electrons can directly receive a large fraction of the viscously dissipated energy in the accretion flow (i. e. delta similar to 0.1-0.5). The radiative efficiency of the hot accretion flow when these two findings are taken into account has not yet been systematically studied, and this is the subject of our paper. We consider two regimes of the hot accretion model: advection-dominated accretion flows that lie in the regime of the low accretion rate, less than or similar to 10 alpha L-2(Edd)/c(2), and the luminous hot accretion flows (LHAFs) that lie above this accretion rate. For the LHAFs, we assume that the accretion flow has a two-phase structure above a certain accretion rate, and we adopt a simplification in our calculation of the dynamics. Our results indicate that the radiative efficiency of hot accretion flow increases with the accretion rate and that it is greatly enhanced by the direct viscous heating to electrons, compared to the previous case of delta << 1. When the accretion rate is high, the radiative efficiency of the hot accretion flow is comparable to that of a standard thin disc. We present fitting formulae of radiative efficiency as a function of accretion rate for various values of delta.
登录
查看更多内容
影响因子：
4.8
作者：
P. Guilbert;M. Rees
通讯作者：
P. Guilbert;M. Rees
影响因子：
2.3
作者：
H. Oda;M. Machida;K. Nakamura;R. Matsumoto
通讯作者：
H. Oda;M. Machida;K. Nakamura;R. Matsumoto
热吸积流内部区域整体康普顿冷却的蒙特卡洛模拟
DOI：
10.1111/j.1365-2966.2009.16135.x
发表时间：
2009-09
影响因子：
4.8
作者：
Niedzwiecki, Andrzej;Yuan, Feng;Zdziarski, Andrzej A.;Xie, Fu-Guo
通讯作者：
Xie, Fu-Guo
影响因子：
2
作者：
E. Blackman;R. Penna;P. Varniere
通讯作者：
E. Blackman;R. Penna;P. Varniere
DOI：
10.1111/j.1365-2966.2011.19127.x
发表时间：
2011-03
影响因子：
4.8
作者：
A. Zdziarski;G. Skinner;G. Pooley;P. Lubiński
通讯作者：
A. Zdziarski;G. Skinner;G. Pooley;P. Lubiński