Small-scale CMB anisotropies induced by the primordial magnetic fields
Small-scale CMB anisotropies induced by the primordial magnetic fields
复制标题
原始磁场引起的小尺度 CMB 各向异性
DOI：
10.1088/1475-7516/2021/03/093
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发表时间：
2021
影响因子：
6.4
通讯作者：
Tashiro Hiroyuki
中科院分区：
文献类型：
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作者：
Minoda Teppei;Ichiki Kiyotomo;Tashiro Hiroyuki
早期宇宙产生的原始磁场（PMFs）被认为是大规模宇宙磁场的起源。由于电磁力和引力相互作用，PMFs被认为在宇宙微波背景（CMB）的各向异性上留下了足迹。在本文中，我们研究了PMFs如何在比CMB光子平均自由程更小的尺度上影响CMB各向异性。我们用由PMFs引起的洛伦兹力解出了重子欧拉方程，并证明了PMFs的矢量型扰动诱导出了丝绸尺度以下的微波背景各向异性，其大小为r > 3000。基于我们的计算，我们对普朗克和南极望远镜（SPT）联合获得的CMB温度各向异性的pmf进行了约束。我们发现，SPT 2017的高分辨温度各向异性在r = 8000处有利于PMF模型，具有较小的尺度依赖性。结果表明，Planck和SPT联合分析对共移1mpc尺度上归一化的PMF强度进行了约束：95% CL时，Planck和SPT数据归一化后的PMF强度为b1 Mpc< 1.5 nG，而95% CL时，Planck数据归一化后的PMF强度仅为b1 Mpc< 3.2 nG。
The primordial magnetic fields (PMFs) produced in the early universe are expected to be the origin of the large-scale cosmic magnetic fields. The PMFs are considered to leave a footprint on the cosmic microwave background (CMB) anisotropies due to both the electromagnetic force and gravitational interaction. In this paper, we investigate how the PMFs affect the CMB anisotropies on smaller scales than the mean-free-path of the CMB photons. We solve the baryon Euler equation with Lorentz force due to the PMFs, and we show that the vector-type perturbations from the PMFs induce the CMB anisotropies below the Silk scale as ℓ> 3000. Based on our calculations, we put a constraint on the PMFs from the combined CMB temperature anisotropies obtained by Planck and South Pole Telescope (SPT). We have found that the highly-resolved temperature anisotropies of the SPT 2017 bandpowers at ℓ≲ 8000 favor the PMF model with a small scale-dependence. As a result, the Planck and SPT's joint-analysis puts a constraint on the PMF strength normalized on the co-moving 1 Mpc scale as B 1 Mpc< 1.5 nG with Planck and SPT at 95% CL, while B 1 Mpc< 3.2 nG only with the Planck data at 95% CL We also discuss the effects on the cosmological parameter estimate when including the SPT data and CMB anisotropies induced by the PMFs.