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Observations of anisotropies in the cosmic microwave background by the Wilkinson Microwave Anisotropy Probe suggest the possibility of oscillations in the primordial density perturbation. Such deviations from the usually assumed scale-free…

Astrophysics · Physics 2011-02-16 Paul Hunt , Subir Sarkar

Anomalies of the cosmic microwave background (CMB) maps have been widely acquainted nowadays from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite to the Planck satellite. One of the anomalies is a multipole alignment from $l=2$ to…

High Energy Astrophysical Phenomena · Physics 2014-06-30 Lixiong Gan , Yuan-Chuan Zou , Zi-Gao Dai

The Einstein field equations of general relativity constrain the local curvature at every point in spacetime, but say nothing about the global topology of the Universe. Cosmic microwave background anisotropies have proven to be the most…

We investigate large-angle scale temperature anisotropy in the Cosmic Microwave Background (CMB) with the Wilkinson Microwave Anisotropy Probe (WMAP) data and model the large-angle anomalies as the effect of the CMB quadrupole anisotropies…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Li-Ping He , Quan Guo

The new Planck constraints on the local bispectrum parameter fnl are about 10^5 times tighter than the current constraints on the trispectrum parameter gnl, which means that the allowed numerical values of the second and third order terms…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-15 Christian T. Byrnes , Sami Nurmi , Gianmassimo Tasinato , David Wands

Scattering of cosmic microwave background (CMB) radiation in galaxy clusters induces a polarization signal proportional to the CMB quadrupole anisotropy at the cluster's location and look-back time. A survey of such remote quadrupole…

Astrophysics · Physics 2007-05-23 Emory F. Bunn

We demonstrate that local, scale-dependent non-Gaussianity can generate cosmic variance uncertainty in the observed spectral index of primordial curvature perturbations. In a universe much larger than our current Hubble volume, locally…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Joseph Bramante , Jason Kumar , Elliot Nelson , Sarah Shandera

We show that cosmological quantum relaxation predicts an anisotropic primordial power spectrum with a specific dependence on wavenumber k. We explore some of the consequences for precision measurements of the cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-12 Antony Valentini

A well-known route to form primordial black holes in the early universe relies on the existence of unusually large primordial curvature fluctuations, confined to a narrow range of wavelengths that would be too small to be constrained by…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-20 Devanshu Sharma , Julien Lesgourgues , Christian T. Byrnes

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 investigate the correlation between the distribution of galaxies and the predicted gravitational-wave background of astrophysical origin. We show that the large angular scale anisotropies of this background are dominated by nearby…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-19 Guadalupe Cañas-Herrera , Omar Contigiani , Valeri Vardanyan

We study the statistics of the primordial power spectrum in models where massless gauge vectors are coupled to the inflaton, paying special attention to observational implications of having fundamental or effective horizons embedded in a…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-07 Mikjel Thorsrud , Federico R. Urban , David F. Mota

We present an efficient numerical code and conduct, for the first time, a null and model-independent CMB test of statistical isotropy using Multipole Vectors (MVs) at all scales. Because MVs are insensitive to the angular power spectrum…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-08 Renan A. Oliveira , Thiago S. Pereira , Miguel Quartin

We investigate the anisotropy in cosmic microwave background Planck maps due to the coupling between its beam asymmetry and uneven scanning strategy. Introducing a pixel space estimator based on the temperature gradients, we find a highly…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-17 Ben Rathaus , Ely D. Kovetz

We study the primordial bispectrum of curvature perturbation in the uniform- density slicing generated by the interaction between the inflaton and isotropic background gauge fields. We derive the action up to cubic order in perturbation and…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-05 Hiroyuki Funakoshi , Kei Yamamoto

Several claims have been made of anomalies in the large-angle properties of the cosmic microwave background anisotropy as measured by WMAP. In most cases, the statistical significance of these anomalies is hard or even impossible to assess,…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-11 Emory F. Bunn

Inflationary cosmology provides a natural mechanism for the generation of primordial perturbations which seed the formation of observed cosmic structure and lead to specific signals of anisotropy in the cosmic microwave background…

Astrophysics · Physics 2011-07-19 Salman Habib , Andreas Heinen , Katrin Heitmann , Gerard Jungman

We show that perturbations generated during the anisotropic pre-inflationary stage of cosmic evolution may affect cosmological observations today for a certain range of parameters. Due to the anisotropic nature of the universe during such…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-15 Pavan K. Aluri , Pankaj Jain

We quantitatively study how the primordial density fluctuations are imprinted on the anisotropy of the phase transition gravitational wave (PTGW). Generated long before recombination and free from Silk damping, the anisotropic PTGW might…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-28 Yongping Li , Fa Peng Huang , Xiao Wang , Xinmin Zhang

We revisit the anisotropic universe model previously developed by Ackerman, Carroll and Wise (ACW), and generalize both the theoretical and computational framework to include polarization and various forms of systematic effects. We apply…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Nicolaas E. Groeneboom , Lotty Ackerman , Ingunn Kathrine Wehus , Hans Kristian Eriksen