Gap-type Particle Acceleration in the Magnetospheres of Rotating Supermassive Black Holes
Gap-type Particle Acceleration in the Magnetospheres of Rotating Supermassive Black Holes
复制标题
DOI：
10.3847/1538-4357/ab8fa1
复制
发表时间：
2020-05
期刊：
影响因子：
--
通讯作者：
G. Katsoulakos;F. Rieger
中科院分区：
文献类型：
--
作者：
G. Katsoulakos;F. Rieger
在活动星系核中探测到快速变化的伽马射线发射，重新引起了人们对磁层粒子加速和发射情景的兴趣。为了探索它的潜力，我们研究了在旋转黑洞磁层零面附近稳定的间隙加速的可能性。我们采用简化的（1D）描述，沿着高斯定律的广义相对论表达式，并且我们假设差距嵌入在辐射低效吸积流的辐射场中。利用该模型导出了平行电场分量、电子和正电子电荷密度、粒子洛伦兹因子和γ光子数密度的径向分布表达式。我们集成的方程组数值，施加适当的边界条件。结果表明，存在一个稳定的间隙解决方案的一个相对较高的整体电流值是在原则上是可能的，如果电荷注入的两个物种被允许在边界。我们提出了不同选择的全球电流和吸积率的间隙解决方案。当放在上下文中时，我们的结果表明，M87中可变的甚高能量γ射线发射可能与磁层起源相一致。
The detection of rapidly variable gamma-ray emission in active galactic nuclei has generated renewed interest in magnetospheric particle acceleration and emission scenarios. In order to explore its potential, we study the possibility of steady gap acceleration around the null surface of a rotating black hole magnetosphere. We employ a simplified (1D) description along with the general relativistic expression of Gauss’s law, and we assume that the gap is embedded in the radiation field of a radiatively inefficient accretion flow. The model is used to derive expressions for the radial distribution of the parallel electric field component, the electron and positron charge density, the particle Lorentz factor, and the number density of γ-ray photons. We integrate the set of equations numerically, imposing suitable boundary conditions. The results show that the existence of a steady gap solution for a relative high value of the global current is in principle possible if charge injection of both species is allowed at the boundaries. We present gap solutions for different choices of the global current and the accretion rate. When put in context, our results suggest that the variable very-high-energy γ-ray emission in M87 could be compatible with a magnetospheric origin.