Jedamzik Karsten, Saveliev Andrey
Laboratoire Univers et Particules de Montpellier, UMR5299-CNRS, Université de Montpellier, 34095 Montpellier, France.
Institute of Physics, Mathematics and Information Technology, Immanuel Kant Baltic Federal University, 236016 Kaliningrad, Russia.
Phys Rev Lett. 2019 Jul 12;123(2):021301. doi: 10.1103/PhysRevLett.123.021301.
Primordial magnetic fields (PMFs), being present before the epoch of cosmic recombination, induce small-scale baryonic density fluctuations. These inhomogeneities lead to an inhomogeneous recombination process that alters the peaks and heights of the large-scale anisotropies of the cosmic microwave background (CMB) radiation. Utilizing numerical compressible MHD calculations and a Monte Carlo Markov chain analysis, which compares calculated CMB anisotropies with those observed by the WMAP and Planck satellites, we derive limits on the magnitude of putative PMFs. We find that the total remaining present day field, integrated over all scales, cannot exceed 47 pG for scale-invariant PMFs and 8.9 pG for PMFs with a violet Batchelor spectrum at 95% confidence level. These limits are more than one order of magnitude more stringent than any prior stated limits on PMFs from the CMB, which have not accounted for this effect.
原初磁场（PMFs）在宇宙复合时期之前就已存在，它会引发小规模的重子密度波动。这些不均匀性导致了不均匀的复合过程，进而改变了宇宙微波背景（CMB）辐射大规模各向异性的峰值和高度。利用数值可压缩磁流体动力学计算以及蒙特卡罗马尔可夫链分析（该分析将计算出的CMB各向异性与威尔金森微波各向异性探测器（WMAP）和普朗克卫星观测到的结果进行比较），我们得出了假定的原初磁场强度的限制。我们发现，对于尺度不变的原初磁场，在95%置信水平下，对所有尺度进行积分后的现今剩余总磁场不能超过47皮高斯（pG）；对于具有紫罗兰色巴彻勒谱的原初磁场，该值不能超过8.9皮高斯。这些限制比之前任何关于CMB原初磁场的规定限制都要严格一个多数量级，之前的限制并未考虑到这种效应。
