arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2103.01943astro-ph.CO
收藏

模拟宇宙网中晕、丝和磁场的排列

On the alignment of haloes, filaments and magnetic fields in the simulated cosmic web

Serena Banfi, Franco Vazza, Claudio Gheller

摘要:

在宇宙网络中,气体和暗物质的连续流动可以产生晕和细丝(以及它们所包含的磁场)的相关动力学性质。有了这项工作,我们研究的晕自旋属性和方向相对于灯丝,和这些对象周围的磁场的形态,晕的质量范围在1 e8 - 1 e14 Msun和灯丝长达8兆秒差距。此外,我们研究这些属性如何变化的存在,或缺乏,不同的(天文)物理过程和不同的磁性初始条件。我们进行宇宙学磁流体动力学模拟与欧拉代码恩佐,我们开发了一个简单而强大的算法来研究三维晕的间接连接。我们调查的形态和磁性,并专注于沿灯丝的磁场的对齐:我们的分析表明,这种对齐的程度是部分依赖于所涉及的物理过程,以及对磁性的初始条件。我们讨论了这种影响的贡献,潜在的尝试来检测周围的磁场这些对象:我们发现,它引入了一个偏置的估计的磁场从法拉第旋转测量技术。具体地说,我们发现河外磁场有很强的倾向与暗条轴对齐,因此磁场的值可以被低估3倍,因为这种效应使得视线磁场(对于在天空平面中的暗条)比总磁场小得多。

英文摘要:

The continuous flow of gas and dark matter across scales in the cosmic web can generate correlated dynamical properties of haloes and filaments (and the magnetic fields they contain). With this work, we study the halo spin properties and orientation with respect to filaments, and the morphology of the magnetic field around these objects, for haloes with masses in the range 1e8-1e14 Msun and filaments up to 8 Mpc long. Furthermore, we study how these properties vary in presence, or lack thereof, of different (astro)physical processes and with different magnetic initial conditions. We perform cosmological magnetohydrodynamical simulations with the Eulerian code Enzo and we develop a simple and robust algorithm to study the filamentary connectivity of haloes in three dimensions. We investigate the morphological and magnetic properties and focus on the alignment of the magnetic field along filaments: our analysis suggests that the degree of this alignment is partially dependent on the physical processes involved, as well as on magnetic initial conditions. We discuss the contribution of this effect on a potential attempt to detect the magnetic field surrounding these objects: we find that it introduces a bias in the estimation of the magnetic field from Faraday rotation measure techniques. Specifically, given the strong tendency we find for extragalactic magnetic fields to align with the filaments axis, the value of the magnetic field can be underestimated by a factor 3, because this effect contributes to making the line-of-sight magnetic field (for filaments in the plane of the sky) much smaller than the total one.

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。

↑