Planck 2013 results. XXIII. Isotropy and statistics of the CMB
Planck Collaboration, P. A. R. Ade, N. Aghanim, C. Armitage-Caplan, M. Arnaud, M. Ashdown, F. Atrio-Barandela, J. Aumont, C. Baccigalupi, A. J. Banday, R. B. Ba… 展开作者
Planck Collaboration, P. A. R. Ade, N. Aghanim, C. Armitage-Caplan, M. Arnaud, M. Ashdown, F. Atrio-Barandela, J. Aumont, C. Baccigalupi, A. J. Banday, R. B. Barreiro, J. G. Bartlett, N. Bartolo, E. Battaner, R. Battye, K. Benabed, A. Benoît, A. Benoit-Lévy, J. -P. Bernard, M. Bersanelli, P. Bielewicz, J. Bobin, J. J. Bock, A. Bonaldi, L. Bonavera, J. R. Bond, J. Borrill, F. R. Bouchet, M. Bridges, M. Bucher, C. Burigana, R. C. Butler, J. -F. Cardoso, A. Catalano, A. Challinor, A. Chamballu, R. -R. Chary, H. C. Chiang, L. -Y Chiang, P. R. Christensen, S. Church, D. L. Clements, S. Colombi, L. P. L. Colombo, F. Couchot, A. Coulais, B. P. Crill, M. Cruz, A. Curto, F. Cuttaia, L. Danese, R. D. Davies, R. J. Davis, P. de Bernardis, A. de Rosa, G. de Zotti, J. Delabrouille, J. -M. Delouis, F. -X. Désert, J. M. Diego, H. Dole, S. Donzelli, O. Doré, M. Douspis, A. Ducout, X. Dupac, G. Efstathiou, F. Elsner, T. A. Enßlin, H. K. Eriksen, Y. Fantaye, J. Fergusson, F. Finelli, O. Forni, M. Frailis, E. Franceschi, M. Frommert, S. Galeotta, K. Ganga, M. Giard, G. Giardino, Y. Giraud-Héraud, J. González-Nuevo, K. M. Górski, S. Gratton, A. Gregorio, A. Gruppuso, F. K. Hansen, M. Hansen, D. Hanson, D. L. Harrison, G. Helou, S. Henrot-Versillé, C. Hernández-Monteagudo, D. Herranz, S. R. Hildebrandt, E. Hivon, M. Hobson, W. A. Holmes, A. Hornstrup, W. Hovest, K. M. Huffenberger, A. H. Jaffe, T. R. Jaffe, W. C. Jones, M. Juvela, E. Keihänen, R. Keskitalo, J. Kim, T. S. Kisner, J. Knoche, L. Knox, M. Kunz, H. Kurki-Suonio, G. Lagache, A. Lähteenmäki, J. -M. Lamarre, A. Lasenby, R. J. Laureijs, C. R. Lawrence, J. P. Leahy, R. Leonardi, C. Leroy, J. Lesgourgues, M. Liguori, P. B. Lilje, M. Linden-Vørnle, M. López-Caniego, P. M. Lubin, J. F. Macías-Pérez, B. Maffei, D. Maino, N. Mandolesi, A. Mangilli, D. Marinucci, M. Maris, D. J. Marshall, P. G. Martin, E. Martínez-González, S. Masi, M. Massardi, S. Matarrese, F. Matthai, P. Mazzotta, J. D. McEwen, P. R. Meinhold, A. Melchiorri, L. Mendes, A. Mennella, M. Migliaccio, K. Mikkelsen, S. Mitra, M. -A. Miville-Deschênes, D. Molinari, A. Moneti, L. Montier, G. Morgante, D. Mortlock, A. Moss, D. Munshi, J. A. Murphy, P. Naselsky, F. Nati, P. Natoli, C. B. Netterfield, H. U. Nørgaard-Nielsen, F. Noviello, D. Novikov, I. Novikov, S. Osborne, C. A. Oxborrow, F. Paci, L. Pagano, F. Pajot, D. Paoletti, F. Pasian, G. Patanchon, H. V. Peiris, O. Perdereau, L. Perotto, F. Perrotta, F. Piacentini, M. Piat, E. Pierpaoli, D. Pietrobon, S. Plaszczynski, D. Pogosyan, E. Pointecouteau, G. Polenta, N. Ponthieu, L. Popa, T. Poutanen, G. W. Pratt, G. Prézeau, S. Prunet, J. -L. Puget, J. P. Rachen, B. Racine, C. Räth, R. Rebolo, M. Reinecke, M. Remazeilles, C. Renault, A. Renzi, S. Ricciardi, T. Riller, I. Ristorcelli, G. Rocha, C. Rosset, A. Rotti, G. Roudier, J. A. Rubiño-Martín, B. Ruiz-Granados, B. Rusholme, M. Sandri, D. Santos, G. Savini, D. Scott, M. D. Seiffert, E. P. S. Shellard, T. Souradeep, L. D. Spencer, J. -L. Starck, V. Stolyarov, R. Stompor, R. Sudiwala, F. Sureau, P. Sutter, D. Sutton, A. -S. Suur-Uski, J. -F. Sygnet, J. A. Tauber, D. Tavagnacco, L. Terenzi, L. Toffolatti, M. Tomasi, M. Tristram, M. Tucci, J. Tuovinen, M. Türler, L. Valenziano, J. Valiviita, B. Van Tent, J. Varis, P. Vielva, F. Villa, N. Vittorio, L. A. Wade, B. D. Wandelt, I. K. Wehus, M. White, A. Wilkinson, D. Yvon, A. Zacchei, A. Zonca
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49 pages, 43 figures, 33 tables. Accepted for publication in A&A
The two fundamental assumptions of the standard cosmological model - that the initial fluctuations are statistically isotropic and Gaussian - are rigorously tested using maps of the cosmic microwave background (CMB) anisotropy from the Planck satellite. Deviations from isotropy have been found and demonstrated to be robust against component separation algorithm, mask choice and frequency dependence. Many of these anomalies were previously observed in the WMAP data, and are now confirmed at similar levels of significance (about 3 sigma). However, we find little evidence for non-Gaussianity, with the exception of a few statistical signatures that seem to be associated with specific anomalies. In particular, we find that the quadrupole-octopole alignment is also connected to a low observed variance of the CMB signal. A power asymmetry is now found to persist to scales corresponding to about l=600, and can be described in the low-l regime by a phenomenological dipole modulation model. However, any primordial power asymmetry is strongly scale-dependent and does not extend to arbitrarily small angular scales. Finally, it is plausible that some of these features may be reflected in the angular power spectrum of the data, which shows a deficit of power on similar scales. Indeed, when the power spectra of two hemispheres defined by a preferred direction are considered separately, one shows evidence for a deficit in power, while its opposite contains oscillations between odd and even modes that may be related to the parity violation and phase correlations also detected in the data. Although these analyses represent a step forward in building an understanding of the anomalies, a satisfactory explanation based on physically motivated models is still lacking.
The isotropy of Hubble expansion in the early and late Universe
University of Chicago（芝加哥大学）；Kavli Institute for Cosmological Physics, University of Chicago（芝加哥大学卡弗里宇宙物理研究所）；Fermi National Accelerator Laboratory（费米国家加速器实验室）；Duke University（杜克大学）
A measurement of the scale of homogeneity in the Early Universe
我们提出的均匀性指数，$\mathcal{H}$，早期宇宙的分形或Hausdorff维数的普朗克宇宙微波背景温度变化$δT$在天空中的第一个测量。各向同性尺度的这种表征是无模型的并且是纯几何的，与$δT$的振幅无关。我们发现证据的均匀性（$\mathcal{H}=0$）的尺度大于$θ_{\mathcal{H}} = 65.9 \pm 9.2 °$的CMB天空。这一发现与$Λ$ CDM预测不一致，后者假设宇宙是尺度不变的。这种异常与角$δT$谱中众所周知的低四极振幅一致，但以直接和模型独立的方式进行量化。我们估计的意义，我们发现$\mathcal{H}=0$使用主成分分析从观测天空的采样变化。假设平移不变性（和平坦几何），我们可以将各向同性尺度$θ_\mathcal{H}$转换成（共动）均匀尺度，这是非常接近所观察到的宇宙学常数$Λ$产生的陷阱表面的协方差矩阵\textcolor{black}{ and simulations, booth base purely on data or in the $Λ$CDM prediction.}的理论预测验证分析。
