Spectral Analysis of Microwave Background Perturbations Induced by Cosmic Strings
Spectral Analysis of Microwave Background Perturbations Induced by Cosmic Strings
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宇宙弦引起的微波背景扰动的频谱分析
DOI：
10.1086/176231
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
L. Perivolaropoulos
中科院分区：
文献类型：
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作者：
L. Perivolaropoulos
利用一个简单的基于种子叠加的解析模型，我们得到了宇宙弦在大于约2armin的所有角尺度上引起的微波背景扰动谱。本文假设在h=1/2的Einstein de Sitter宇宙中存在标准复合，研究了沿天空中沿着一个大圆的涨落谱。
多普勒和潜在的最后散射表面上的扰动（萨克斯-沃尔夫效应）占主导地位的后重组扰动的尺度小于约2度。使用对应于COBE实验的滤波函数，我们得到了一个有效的功率谱指数$n_{eff}\simeq 1.35$与最近公布的第二年COBE数据显示$n_{eff}\simeq 1.5$很好地吻合。弦模型的唯一自由参数（$G\mu$）通过对COBE检测进行归一化而固定，从而得到$G\mu=1.6$。其他参数（例如，{\it rms}弦速度）通过与弦模拟进行比较而固定。使用这些参数值，我们比较了正在进行的实验（特内里费岛，SP 91，MAX，OVRO等）预测的温度波动$（{{\Delta T}\over T}）_{\it rms}$与检测和相应的预测暴胀模型。
Using a simple analytic model based on seed superposition we obtain the spectrum of microwave background perturbations induced by cosmic strings on all angular scales larger than about 2 armin. We assume standard recombination in an Einstein de Sitter universe with $h=1/2$ and study the fluctuation spectrum along a great circle in the sky.
Doppler and potential perturbations on the last scattering surface (Sachs-Wolfe effect) are shown to dominate over post-recombination perturbations on scales smaller than about 2 degrees. Using a filter function corresponding to the COBE experiment we obtain an effective power spectrum index $n_{eff}\simeq 1.35$ in good agreement with the recently announced second year COBE data showing $n_{eff}\simeq 1.5$. The only free parameter ($G\mu$) of the string model is fixed by normalizing on the COBE detection leading to $G\mu=1.6$. Other parameters (e.g. the {\it rms} string velocity) are fixed by comparing with string simulations. Using these parameter values we compare the {\it rms} temperature fluctuations $({{\Delta T}\over T})_{\it rms}$ predicted for ongoing experiments (Tenerife, SP91, MAX, OVRO etc) with detections and with the corresponding predictions of inflationary models.