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arXiv 1402.0870astro-ph.COphysics.data-an
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用局部方差估计量测量的WMAP和普朗克温度天空图中的功率不对称性

Power asymmetry in WMAP and Planck temperature sky maps as measured by a local variance estimator

Y. Akrami, Y. Fantaye, A. Shafieloo, H. K. Eriksen, F. K. Hansen, A. J. Banday, K. M. Górski

摘要:

我们重新审视半球功率不对称的问题,在WMAP和普朗克温度天空图通过测量当地的差异在天空中,并在磁盘上的各种大小。对于2013年的普朗克天空图,我们发现1000个可用的各向同性普朗克“全焦平面”模拟中没有一个具有比从数据估计的更大的方差不对称性,这表明至少在$3.3σ$水平上存在形式上显著的各向异性特征。对于WMAP 9年的数据,我们发现1000个模拟中有5个具有较大的不对称性。从普朗克数据的不对称性的首选方向是$(l,b)=(212^\circ,-13^\circ)$,在良好的协议与以前的报告相同的半球功率不对称。

英文摘要:

We revisit the question of hemispherical power asymmetry in the WMAP and Planck temperature sky maps by measuring the local variance over the sky and on disks of various sizes. For the 2013 Planck sky map we find that none of the 1000 available isotropic Planck "Full Focal Plane" simulations have a larger variance asymmetry than that estimated from the data, suggesting the presence of an anisotropic signature formally significant at least at the $3.3σ$ level. For the WMAP 9-year data we find that 5 out of 1000 simulations have a larger asymmetry. The preferred direction for the asymmetry from the Planck data is $(l,b)=(212^\circ,-13^\circ)$, in good agreement with previous reports of the same hemispherical power asymmetry.

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