论文标题
Ngauss原始磁场在CMB的B模式极化中的可检测性
Detectability of nGauss primordial magnetic fields in the B-mode polarization of CMB
论文作者
论文摘要
宇宙中大型磁场的起源仍然未知。观察表明，在最后一个散射表面存在Ngauss原始磁场。此类领域的存在将影响宇宙学扰动的演变，并可能在CMB各向异性上留下烙印。在这里，我们表明B模式功率谱将随机原始磁场的明确特征带到几个Ngauss。具体而言，Ngauss原始磁场的存在在所有尺度上都会改变BB功率谱。在大尺度上，张量模式有助于B模式频谱，而非散矢量模式则在小尺度上贡献。我们表明，CMB的B模式具有原始磁场的独特特征。为了验证我们的预测，我们使用Bicep2和Polarbear数据，并发现实验中的B模式观察结果与非零的原始场一致。我们还使用二头肌观测来限制原始磁场。我们提供了具有原始磁场的CMB的B模式极化的详细分析，并研究了对即将到来的CMB任务的影响。
The origin of large-scale magnetic fields in the Universe is still unknown. Observations suggest the presence of nGauss primordial magnetic fields at the last scattering surface. The presence of such fields will affect the evolution of cosmological perturbations and potentially leave an imprint on the CMB anisotropies. Here, we show that the B-mode power spectrum carries a clear signature of the stochastic primordial magnetic fields up to a few nGauss. Specifically, the presence of nGauss primordial magnetic fields changes the BB power spectrum at all scales. At large scales, the tensor modes contribute to the B-mode spectrum, while non-vanishing vector modes contribute at small scales. We show that the B-mode of CMB carry a distinct signature of the primordial magnetic fields. To validate our prediction, we use BICEP2 and POLARBEAR data and find that B-mode observations from the experiments are consistent with non-zero primordial fields. We also use the BICEP2 observations to constrain the primordial magnetic field. We provide a detailed analysis of the B-mode polarization of the CMB with primordial magnetic fields and investigate the implications for the upcoming CMB missions.
