arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 2102.07986astro-ph.HEastro-ph.GA
收藏

黑洞驱动的广义相对论性强磁化喷流的物质密度分布

Matter density distribution of general relativistic highly magnetized jets driven by black holes

Taiki Ogihara, Takumi Ogawa, Kenji Toma

摘要:

高分辨率甚长基线干涉测量(VLBI)射电观测已经解决了详细的发射结构的活动星系核喷流。广义相对论磁流体动力学(GRMHD)模拟已经提高了对喷流产生物理的理解,尽管理论研究在约束喷射物质的起源和分布方面仍然存在困难。我们构造了一个新的稳态轴对称GRMHD喷流模型,得到了黑洞磁层的近似解,并研究了喷流的物质密度分布。通过假设模拟无力解析解和GRMHD模拟结果的固定极向磁场形状,并假设在分离表面处的恒定极向速度,该分离表面将流入和流出分开,我们数值地解决了分离表面处的磁力线之间的力平衡,并解析地解决了沿磁力线的物质速度和密度的分布。我们发现,在我们的抛物场模型中的分离表面的密度大致遵循$\propto r_{ss}^{-2}$在远离BH的区域,其中$r_{ss}$是分离表面的半径。当BH自旋较大或分离表面处的速度较小时,分离表面处的密度变得更集中于射流边缘附近。我们的半解析模型,结合辐射转移计算,可能有助于解释高分辨率VLBI观测和理解喷射物质的起源。

英文摘要:

High-resolution very long baseline interferometry (VLBI) radio observations have resolved the detailed emission structures of active galactic nucleus jets. General relativistic magnetohydrodynamic (GRMHD) simulations have improved the understanding of jet production physics, although theoretical studies still have difficulties in constraining the origin and distribution of jetted matter. We construct a new steady, axisymmetric GRMHD jet model to obtain approximate solutions of black hole (BH) magnetospheres, and examine the matter density distribution of jets. By assuming fixed poloidal magnetic field shapes that mimic force-free analytic solutions and GRMHD simulation results and assuming constant poloidal velocity at the separation surface, which divides the inflow and outflow, we numerically solve the force-balance between the field lines at the separation surface and analytically solve the distributions of matter velocity and density along the field lines. We find that the densities at the separation surface in our parabolic field models roughly follow $\propto r_{ss}^{-2}$ in the far zone from the BH, where $r_{ss}$ is the radius of the separation surface. When the BH spin is larger or the velocity at the separation surface is smaller, the density at the separation surface becomes concentrated more near the jet edge. Our semi-analytic model, combined with radiative transfer calculations, may help interpret the high-resolution VLBI observations and understand the origin of jetted matter.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑