Cosmic microwave background anisotropies generated by cosmic strings with small-scale structure
Cosmic microwave background anisotropies generated by cosmic strings with small-scale structure
复制标题
小尺度结构宇宙弦产生的宇宙微波背景各向异性
DOI：
10.1088/1475-7516/2023/07/016
复制
发表时间：
2023
影响因子：
6.4
通讯作者：
I. Rybak
中科院分区：
文献类型：
--
作者：
Rodrigo P. Silva;Lara Sousa;I. Rybak
我们研究了扭结对宇宙弦网络产生的宇宙微波背景（CMB）各向异性的影响。为了做到这一点，我们扩展了未连接段模型来描述具有扭结的宇宙弦网络的应力-能量张量，并在CMBACT中实现了这种扩展，以计算这些波动弦网络产生的CMB各向异性。我们的研究结果表明，包括扭结导致，在一般情况下，到增强的温度和偏振角功率谱，当与宇宙弦网络产生的没有小尺度结构具有相同的能量密度相比，对应于扭结之间的距离尺度。这种增强在温度各向异性的情况下更加突出，本质上是由矢量模各向异性的显著增加引起的，因为扭结由于它们的形状而产生物质的涡旋运动--这是一种在诉诸于对摆动的宇宙弦的有效描述时没有考虑到的现象。这些结果，虽然使用一个简化的字符串配置，其中的interkink距离和它们的锐度保持固定，似乎表明，明确列入扭结可能是必不可少的，以执行更准确的预测宇宙弦产生的CMB各向异性小尺度。
We study the impact of kinks on the cosmic microwave background (CMB) anisotropies generated by cosmic string networks. To do so, we extend the Unconnected Segment Model to describe the stress-energy tensor of a network of cosmic strings with kinks and implement this extension in CMBACT to compute the CMB anisotropies generated by these wiggly string networks. Our results show that the inclusion of kinks leads, in general, to an enhancement of the temperature and polarization angular power spectra, when compared to those generated by cosmic string networks without small-scale structure with the same energy density, on scales corresponding to the distance between kinks. This enhancement, that is more prominent in the case of the temperature anisotropies, is essentially caused by a significant increase of the vector-mode anisotropies, since kinks, due to their shape, generate vortical motions of matter — a phenomenon that is not taken into account when resorting to an effective description of wiggly cosmic strings. These results, although derived using a simplified string configuration in which the interkink distance and their sharpness remain fixed, seem to indicate that the explicit inclusion of kinks may be essential to perform more accurate predictions of the CMB anisotropies generated by cosmic strings on small scales.