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We scrutinize the reported lensing anomaly of the CMB by considering several phenomenological modifications of the lensing consistency parameter, $A_{\rm L}$. Considering Planck spectra alone, we find statisically significant evidence for…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-23 Ido Ben-Dayan , Utkarsh Kumar , Meir Shimon , Amresh Verma

The large-angle (low-l) correlations of the Cosmic Microwave Background exhibit several statistically significant anomalies compared to the standard inflationary big-bang model, however no connection has hitherto been drawn between them.…

Astrophysics · Physics 2009-11-10 Dominik J. Schwarz , Glenn D. Starkman , Dragan Huterer , Craig J. Copi

In recent years, large radio surveys of Active Galactic Nuclei (AGNs), comprising millions of sources, have become available where one could investigate dipole asymmetries, assumedly arising due to a peculiar motion of the Solar system.…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-21 Ashok K. Singal

We review the recently found large-scale anomalies in the maps of temperature anisotropies in the cosmic microwave background. These include alignments of the largest modes of CMB anisotropy with each other and with geometry and direction…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-10 Craig J. Copi , Dragan Huterer , Dominik J. Schwarz , Glenn D. Starkman

Inspired by a dipole asymmetric template for the CMB temperature map in the primordial scalar fluctuations observed by Planck at a large scale, we examine the contribution of a similar template for power asymmetry in modifying the linear…

General Relativity and Quantum Cosmology · Physics 2023-08-01 Jafar Khodagholizadeh , Rohoollah Mohammadi , S. M. S. Movahed

The standard cosmological model predicts statistically isotropic cosmic microwave background (CMB) fluctuations characterized by the CMB temperature coefficients $a_{\ell m}$ being independent Gaussian random variables with zero mean and…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-17 Joann Jones , Craig J. Copi , Glenn D. Starkman , Yashar Akrami

In this study, we revisit the well-known cosmic microwave background (CMB) anomaly referred to as Hemispherical Power Asymmetry (HPA), using CMB temperature maps from the Planck mission public release 4 (PR4) and the WMAP nine-year data…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-21 Sanjeev Sanyal , Pavan Kumar Aluri , Arman Shafieloo

The origin of power asymmetry and other measures of statistical anisotropy on the largest scales of the universe, as manifested in Cosmic Microwave Background (CMB) and large-scale structure data, is a long-standing open question in…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-12 Pablo Fosalba , Enrique Gaztanaga

The remarkable progress in cosmic microwave background (CMB) studies over past decade has led to the era of precision cosmology in striking agreement with the $\Lambda$CDM model. However, the lack of power in the CMB temperature…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-09 Asif Iqbal , Jayanti Prasad , Tarun Souradeep , Manzoor A. Malik

The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at l~20 and bump at l~40. One explanation for this structure is the presence of features in the primordial curvature…

Cosmology and Nongalactic Astrophysics · Physics 2009-05-19 Michael J. Mortonson , Cora Dvorkin , Hiranya V. Peiris , Wayne Hu

We investigate a possible asymmetry in the statistical properties of the cosmic microwave background temperature field and to do so we construct an estimator aiming at detecting a dipolar modulation. Such a modulation is found to induce…

Astrophysics · Physics 2009-11-10 Simon Prunet , Jean-Philippe Uzan , Francis Bernardeau , Tristan Brunier

The largest anisotropy in the cosmic microwave background (CMB) is the 3 mK kinematic dipole reflecting our motion with respect to the CMB frame and pointed in the direction $(l, b) = (264^\circ, +48^\circ)$ in Galactic coordinates. We…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-19 James Creswell , Pavel Naselsky

The lack of power of large--angle CMB anisotropies is known to increase its statistical significance at higher Galactic latitudes, where a string--inspired pre--inflationary scale $\Delta$ can also be detected. Considering the Planck 2015…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-13 A. Gruppuso , N. Kitazawa , M. Lattanzi , N. Mandolesi , P. Natoli , A. Sagnotti

In this article we propose a novel test for statistical anisotropy of the CMB. The test is based on the fact, that the Galactic foregrounds have a remarcably strong symmetry with respect to their antipodal points and with respect to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 P. Naselsky , M. Hansen , J. Kim

In recent years the goal of estimating different cosmological parameters precisely has set new challenges in the effort to accurately measure the angular power spectrum of CMB. This has required removal of foreground contamination as well…

Astrophysics · Physics 2008-11-26 Rajib Saha , Simon Prunet , Pankaj Jain , Tarun Souradeep

Parity violating extensions of the standard electromagnetic theory cause in vacuo rotation of the plane of polarization of propagating photons. This effect, also known as cosmic birefringence, impacts the cosmic microwave background (CMB)…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-14 Planck Collaboration , N. Aghanim , M. Ashdown , J. Aumont , C. Baccigalupi , M. Ballardini , A. J. Banday , R. B. Barreiro , N. Bartolo , S. Basak , K. Benabed , J. -P. Bernard , M. Bersanelli , P. Bielewicz , L. Bonavera , J. R. Bond , J. Borrill , F. R. Bouchet , C. Burigana , E. Calabrese , J. -F. Cardoso , J. Carron , H. C. Chiang , L. P. L. Colombo , B. Comis , D. Contreras , F. Couchot , A. Coulais , B. P. Crill , A. Curto , F. Cuttaia , P. de Bernardis , A. de Rosa , G. de Zotti , J. Delabrouille , F. -X. Désert , E. Di Valentino , C. Dickinson , J. M. Diego , O. Doré , A. Ducout , X. Dupac , S. Dusini , F. Elsner , T. A. Enßlin , H. K. Eriksen , Y. Fantaye , F. Finelli , F. Forastieri , M. Frailis , E. Franceschi , A. Frolov , S. Galeotta , S. Galli , K. Ganga , R. T. Génova-Santos , M. Gerbino , Y. Giraud-Héraud , J. González-Nuevo , K. M. Górski , A. Gruppuso , J. E. Gudmundsson , F. K. Hansen , S. Henrot-Versillé , D. Herranz , E. Hivon , Z. Huang , A. H. Jaffe , W. C. Jones , E. Keihänen , R. Keskitalo , K. Kiiveri , N. Krachmalnicoff , M. Kunz , H. Kurki-Suonio , J. -M. Lamarre , M. Langer , A. Lasenby , M. Lattanzi , C. R. Lawrence , M. Le Jeune , J. P. Leahy , F. Levrier , M. Liguori , P. B. Lilje , V. Lindholm , M. López-Caniego , Y. -Z. Ma , J. F. Macías-Pérez , G. Maggio , D. Maino , N. Mandolesi , M. Maris , P. G. Martin , E. Martínez-González , S. Matarrese , N. Mauri , J. D. McEwen , P. R. Meinhold , A. Melchiorri , A. Mennella , M. Migliaccio , M. -A. Miville-Deschênes , D. Molinari , A. Moneti , G. Morgante , A. Moss , P. Natoli , L. Pagano , D. Paoletti , G. Patanchon , L. Patrizii , L. Perotto , V. Pettorino , F. Piacentini , L. Polastri , G. Polenta , J. P. Rachen , B. Racine , M. Reinecke , M. Remazeilles , A. Renzi , G. Rocha , C. Rosset , M. Rossetti , G. Roudier , J. A. Rubiño-Martín , B. Ruiz-Granados , M. Sandri , M. Savelainen , D. Scott , C. Sirignano , G. Sirri , L. D. Spencer , A. -S. Suur-Uski , J. A. Tauber , D. Tavagnacco , M. Tenti , L. Toffolatti , M. Tomasi , M. Tristram , T. Trombetti , J. Valiviita , F. Van Tent , P. Vielva , F. Villa , N. Vittorio , B. D. Wandelt , I. K. Wehus , A. Zacchei , A. Zonca

We explore a model of the early universe in which the inflationary epoch is preceded by a cosmic bounce, and argue that this scenario provides a common origin to several of the anomalous features that have been observed at large angular…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-17 Ivan Agullo , Dimitrios Kranas , V. Sreenath

We investigate the hemispherical power asymmetry observed in the CMBR by attributing it to an early inhomogeneous phase of cosmic expansion. Unlike the conventional assumption of a perfectly isotropic and homogeneous pre-inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-30 Akash Gandhi , Mohit Panwar , Pankaj Jain

Since the temperature fluctuations in cosmic microwave background (CMB) on large-angular scales probe length scales that were super-horizon sized at photon decoupling and hence insensitive to microphysical processes, the low-multipole CMB…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-30 Cheng Cheng , Qing-Guo Huang

Accurate measurements of angular power spectrum of Cosmic Microwave Background (CMB) radiation has lead to marked improvement in the estimates of different cosmological parameters. This has required removal of foreground contamination as…

Astrophysics · Physics 2009-11-13 Rajib Saha , Pankaj Jain , Tarun Souradeep