论文标题
宇宙黎明期间的原始磁场，边缘21 cm信号
Primordial magnetic fields during the cosmic dawn in light of EDGES 21-cm signal
论文作者
论文摘要
我们研究了限制原始磁场（PMF）及其在黑暗时代和宇宙黎明期间的进化前景，并根据边缘21 cm信号。我们的分析是在“较冷的IgM”背景上进行的，该背景是解释边缘信号的有前途的途径之一。我们考虑过度冷却的暗物质 - 巴里昂相互作用。我们发现，较冷的IgM抑制了剩余的无电子分数以及离子化和中性成分之间的耦合系数。康普顿的加热也会在较冷的IGM背景下受到影响。因此，与标准方案相比，由于PMF引起的IgM加热速率提高了。因此，与简单的$（1+Z）^2 $相比，在黑暗年龄和宇宙黎明时，很大一部分的磁能，对于$ b_0 \ lyssim 0.5 \，{\ rm ng} $，以更快的速度传递到IGM，并且磁场衰减的速度要快得多。这种低PMF是解释较低红移时边缘吸收信号的上升的不可能的候选者。我们还看到，PMF和DM-Baryon相互作用一起引入了IGM温度的红移演化中的平稳状特征。我们发现，PMF的上限取决于基础DM-Baryon相互作用。当相互作用横截面更高和/或DM颗粒质量较低时，可以允许更高的PMF。我们的研究表明，如果考虑使用合适的横截面和DM质量的DM-Baryon交互，则可以允许使用标准模型中排除的$ b_0 $ $ \ sim 0.4 \，{\ rm ng} $。
We study prospects of constraining the primordial magnetic field (PMF) and its evolution during the dark ages and cosmic dawn in light of EDGES 21-cm signal. Our analysis has been carried out on a `colder IGM' background which is one of the promising avenues to interpret the EDGES signal. We consider the dark matter-baryon interactions for the excess cooling. We find that the colder IGM suppresses both the residual free electron fraction and the coupling coefficient between the ionised and neutral components. The Compton heating also gets affected in colder IGM background. Consequently, the IGM heating rate due to the PMF enhances compared to the standard scenario. Thus, a significant fraction of the magnetic energy, for $B_0 \lesssim 0.5 \, {\rm nG}$, gets transferred to the IGM and the magnetic field decays at a much faster rate compared to the simple $(1+z)^2$ scaling during the dark ages and cosmic dawn. This low PMF is an unlikely candidate for explaining the rise of the EDGES absorption signal at lower redshift. We also see that the PMF and DM-baryon interaction together introduces a plateau-like feature in the redshift evolution of the IGM temperature. We find that the upper limit on the PMF depends on the underlying DM-baryon interaction. Higher PMF can be allowed when the interaction cross-section is higher and/or the DM particle mass is lower. Our study shows that the PMF with $B_0$ up to $\sim 0.4 \, {\rm nG}$, which is ruled out in the standard model, can be allowed if DM-baryon interaction with suitable cross-section and DM mass is considered.
