Large scale CMB anomalies from thawing cosmic strings
Large scale CMB anomalies from thawing cosmic strings
复制标题
宇宙弦解冻导致大规模宇宙微波背景异常
DOI：
10.1088/1475-7516/2016/02/033
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
F. R. Bouchet
中科院分区：
文献类型：
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作者：
C. Ringeval;D. Yamauchi;J. Yokoyama;F. R. Bouchet
在暴胀过程中形成的宇宙弦预计要么在超哈勃距离上被稀释，即今天不可见，要么最近穿过我们过去的光锥。我们讨论后一种情况，其中一些字符串的印记在宇宙微波背景（CMB）各向异性重组后，他们的签名。由于几乎冻结在哈勃流中，这些弦是准静态的，几乎避开了所有以前推导出的对它们张力的约束，同时能够在CMB天空中产生大尺度的各向异性。使用本地方差估计数以千计的数值模拟南武-后藤所有的天空地图，我们计算预期的信号，并表明它可以模仿偶极子调制在大角度尺度，而在小角度可以忽略不计。有趣的是，这样一个场景通常会从宇宙弦环的解冻中产生一个冷点。与暴胀起源的各向异性相混合，我们发现一些张力弦GU= Script O（1）× 10− 6与普朗克卫星测量中报道的偶极调制的振幅相匹配，并且可能是其他大尺度异常的起源。
Cosmic strings formed during inflation are expected to be either diluted over super-Hubble distances, ie, invisible today, or to have crossed our past light cone very recently. We discuss the latter situation in which a few strings imprint their signature in the Cosmic Microwave Background (CMB) Anisotropies after recombination. Being almost frozen in the Hubble flow, these strings are quasi static and evade almost all of the previously derived constraints on their tension while being able to source large scale anisotropies in the CMB sky. Using a local variance estimator on thousand of numerically simulated Nambu-Goto all sky maps, we compute the expected signal and show that it can mimic a dipole modulation at large angular scales while being negligible at small angles. Interestingly, such a scenario generically produces one cold spot from the thawing of a cosmic string loop. Mixed with anisotropies of inflationary origin, we find that a few strings of tension GU= Script O (1)× 10− 6 match the amplitude of the dipole modulation reported in the Planck satellite measurements and could be at the origin of other large scale anomalies.