A Novel Mechanism for the Formation of Electron-Positron Outflow from Hot Accretion Disks
A Novel Mechanism for the Formation of Electron-Positron Outflow from Hot Accretion Disks
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热吸积盘正电子流出形成的新机制
DOI：
10.1086/312245
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
M. Kusunose
中科院分区：
文献类型：
--
作者：
T. Yamasaki;F. Takahara;M. Kusunose
提出了在活动星系核和星系黑洞双星中形成相对论性流出的一种机制，即在这些物体的双温吸积盘中产生的电子-正电子对的喷射。我们在单区近似中求解对动量方程，其中我们假设电子-正电子成分可以独立于形成流体静力大气的电子-质子成分逃逸。结果表明，在圆盘内部区域，当质量吸积速率大于爱丁顿速率的十分之一时，粘性耗散的能量大部分转化为喷射出的电子-正电子对的热能和动能。产生的粒子对在垂直方向上是由它们自身的气体压力而不是由辐射力加速的。正如最近对活动星系核和星系天体的观测所表明的那样，这种机制成功地提取了吸积能力，从而形成了强大的电子-正电子流出。
A mechanism is proposed for the formation of relativistic outflows in active galactic nuclei and Galactic black hole binaries, i.e., the ejection of electron-positron pairs produced in two-temperature accretion disks in those objects. We solve the pair-momentum equation in the one-zone approximation, in which we assume that the electron-positron component can escape independently of the electron-proton component that forms a hydrostatic atmosphere. The results show that, in the inner regions of the disks, when the mass accretion rate becomes larger than about a tenth of the Eddington rate, most of the viscously dissipated energy is converted into the thermal and kinetic energy of the ejected electron-positron pairs. The produced pairs are accelerated in the vertical direction by their own gas pressure rather than by the radiative force. This mechanism is thus successful in extracting accretion power so as to form powerful electron-positron outflows, as suggested by recent observations of active galactic nuclei and Galactic objects.