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arXiv 1709.03599astro-ph.CO
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透镜协方差对CMB功率谱似然分析的影响

Lens covariance effects on likelihood analyses of CMB power spectra

Pavel Motloch, Wayne Hu

摘要:

由引力透镜在CMB功率谱中引起的非高斯相关性必须包括在未来CMB实验的可能性分析中。我们提出了一个简单但准确的似然模型,其中包括这些相关性和使用它的马尔可夫链蒙特卡罗参数估计从模拟透镜CMB地图的上下文中的$Λ$ CDM和扩展,其中包括中微子质量或暗能量状态方程的总和$w$。如果CMB-S4型实验不考虑透镜诱导的协方差,则每种情况下一种参数组合的误差将被低估超过2倍,并且$w$的下限可能被严重错误估计。错误地排除真实模型或发现与其他数据集的紧张关系的频率也会大幅增加。我们的分析还使分离的镜头和unlensed信息从CMB功率谱,这提供了一致性测试的模型,如果与其他这样的测量相结合,一个几乎镜头样本方差免费测试系统学和新的物理在unlensed光谱。这种参数化也导致了一个简单有效的可能性,可以用来帮助建立模型的情况下,一致性测试的$Λ$ CDM失败。

英文摘要:

Non-Gaussian correlations induced in CMB power spectra by gravitational lensing must be included in likelihood analyses for future CMB experiments. We present a simple but accurate likelihood model which includes these correlations and use it for Markov Chain Monte Carlo parameter estimation from simulated lensed CMB maps in the context of $Λ$CDM and extensions which include the sum of neutrino masses or the dark energy equation of state $w$. If lensing-induced covariance is not taken into account for a CMB-S4 type experiment, the errors for one combination of parameters in each case would be underestimated by more then a factor of two and lower limits on $w$ could be misestimated substantially. The frequency of falsely ruling out the true model or finding tension with other data sets would also substantially increase. Our analysis also enables a separation of lens and unlensed information from CMB power spectra, which provides for consistency tests of the model and, if combined with other such measurements, a nearly lens-sample-variance free test for systematics and new physics in the unlensed spectrum. This parameterization also leads to a simple effective likelihood that can be used to assist model building in case consistency tests of $Λ$CDM fail.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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