arXiv 1601.010592016-01-06astro-ph.CO

弦网络的原始磁场

Primordial magnetic fields from the string network

Kouichirou Horiguchi, Kiyotomo Ichiki, Naoshi Sugiyama

备注：: 17 pages, 3 figures

摘要：

宇宙弦是早期宇宙中由破缺相变形成的一种宇宙缺陷。单个的弦会聚集在一起形成一个网络，它们的动力学运动会引起标量、矢量和张量类型的扰动。本文在单尺度模型的基础上研究了弦网络中的矢量模扰动，计算了相应的磁场的时间演化和功率谱。我们证明，基于标准宇宙学，弦网络诱导的光子和重子流体之间的相对速度可以产生宽范围的磁场。在同动坐标系下，我们得到了复合前的磁场谱在超视界尺度上为$a^2B(k,z)\sim4\times10^{-16}Gμ/((1+z)/1000)^{4.25}(k/{\rm Mpc}^{-1})^{3.5}$高斯，在亚视界尺度上为$a^2B(k,z)\sim2.4\times10^{-17}Gμ/((1+z)/1000)^{3.5}(k/{\rm Mpc}^{-1})^{2.5}$高斯。该磁场增长到复合的末端，并且在现今的$k\sim1\ {\rm Mpc}^{-1}$尺度下具有近似为$B\sim10^{-17\sim -18} Gμ$高斯的最终振幅。这个磁场可能是宇宙磁场的种子。

英文摘要：

Cosmic strings are a type of cosmic defect formed by a symmetry-breaking phase transition in the early universe. Individual strings would have gathered to build a network, and their dynamical motion would induce scalar--, vector-- and tensor--type perturbations. In this paper, we focus on the vector mode perturbations arising from the string network based on the one scale model and calculate the time evolution and the power spectrum of the associated magnetic fields. We show that the relative velocity between photon and baryon fluids induced by the string network can generate magnetic fields over a wide range of scales based on standard cosmology. We obtain the magnetic field spectrum before recombination as $a^2B(k,z)\sim4\times10^{-16}Gμ/((1+z)/1000)^{4.25}(k/{\rm Mpc}^{-1})^{3.5}$ Gauss on super-horizon scales, and $a^2B(k,z)\sim2.4\times10^{-17}Gμ/((1+z)/1000)^{3.5}(k/{\rm Mpc}^{-1})^{2.5}$ Gauss on sub-horizon scales in co-moving coordinates. This magnetic field grows up to the end of recombination, and has a final amplitude of approximately $B\sim10^{-17\sim -18} Gμ$ Gauss at the $k\sim1\ {\rm Mpc}^{-1}$ scale today. This field might serve as a seed for cosmological magnetic fields.

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。

摘要：

英文摘要：

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