Non-Gaussianity in the Cosmic Microwave Background temperature fluctuations from cosmic (super-)strings
Non-Gaussianity in the Cosmic Microwave Background temperature fluctuations from cosmic (super-)strings
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DOI：
10.1088/1475-7516/2009/10/003
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发表时间：
2008-11
影响因子：
6.4
通讯作者：
Keitaro Takahashi;A. Naruko;Y. Sendouda;Daisuke Yamauchi;Chul-Moon Yoo;M. Sasaki
中科院分区：
文献类型：
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作者：
Keitaro Takahashi;A. Naruko;Y. Sendouda;Daisuke Yamauchi;Chul-Moon Yoo;M. Sasaki
我们计算解析的小尺度温度波动的宇宙微波背景从宇宙（超）字符串和研究的依赖字符串intercommuting概率P.我们开发了一个分析模型，描述了一个字符串网络的演变和计算的字符串段和扭结的数量在一个地平线卷。然后，我们推导出的概率分布函数（pdf），其中考虑到有限的角分辨率的观察。由此产生的PDF由高斯部分，由于频繁的散射长字符串段和非高斯尾巴，由于密切接触扭结。高斯部分的色散与Fraisse等人通过数值模拟获得的色散相当一致。另一方面，非高斯尾包含两个唯象参数，这是通过与P = 1的数值结果比较确定的。将pdf外推到P < 1的情况，我们预测对于小P，非高斯特征被抑制。
We compute analytically the small-scale temperature fluctuations of the cosmic microwave background from cosmic (super-)strings and study the dependence on the string intercommuting probability P. We develop an analytical model which describes the evolution of a string network and calculate the numbers of string segments and kinks in a horizon volume. Then we derive the probability distribution function (pdf) which takes account of finite angular resolution of observation. The resultant pdf consists of a Gaussian part due to frequent scatterings by long string segments and a non-Gaussian tail due to close encounters with kinks. The dispersion of the Gaussian part is reasonably consistent with that obtained by numerical simulations by Fraisse et al.. On the other hand, the non-Gaussian tail contains two phenomenological parameters which are determined by comparison with the numerical results for P = 1. Extrapolating the pdf to the cases with P < 1, we predict that the non-Gaussian feature is suppressed for small P.