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arXiv 1503.01611astro-ph.CO
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$\mathbfΛ$ CDM和偶极模型中的CMB低多极对齐

CMB low multipole alignments in the $\mathbfΛ$CDM and Dipolar models

L. Polastri, A. Gruppuso, P. Natoli

摘要:

偶极模型\cite{Gordon:2005ai}由于可以从唯象上解释WMAP和Planck数据中发现的CMB半球功率不对称性而引起了人们的极大兴趣。由于这样一个模型在大的角度尺度上明确地打破了各向同性,因此很自然地想知道它是否也可以解释其他的CMB方向异常。通过对低$\ell$配向的研究,并假设$Λ$ CDM,我们证实了四极/八极和偶极/四极/八极配向是异常的,其显著性可达$99.9\%$ C.L.,WMAP和Planck的数据。此外,我们第一次表明,这样的功能也是异常的偶极模型,大致在同一水平的$Λ$ CDM。我们的结论是,偶极模型并没有提供一个更好的拟合数据比$Λ$ CDM。

英文摘要:

The dipolar model \cite{Gordon:2005ai} has attracted much interest because it may phenomenologically explain the CMB hemispherical power asymmetry found in the WMAP and Planck data. Since such a model explicitly breaks isotropy at large angular scales it is natural to wonder whether it can also explain other CMB directional anomalies. Focusing on the low $\ell$ alignments and assuming $Λ$CDM, we confirm that the quadrupole/octupole and the dipole/quadrupole/octupole alignments are anomalous with a significance up to $99.9\%$ C.L., for both WMAP and Planck data. Moreover, we show for the first time that such features are anomalous also in the dipolar model, roughly at the same level as in $Λ$CDM. We conclude that the dipolar model does not provide a better fit to the data than the $Λ$CDM.

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