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Measurements of the cosmic microwave background (CMB) temperature anisotropies have revealed a dipolar asymmetry in power at the largest scales, in apparent contradiction with the statistical isotropy of standard cosmological models. The…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-07 D. Contreras , J. Hutchinson , A. Moss , D. Scott , J. P. Zibin

We have analyzed the available polarization surveys of the Galactic emission to estimate to what extent it may be a serious hindrance to forthcoming experiments aimed at detecting the polarized component of Cosmic Microwave Background (CMB)…

Astrophysics · Physics 2009-10-31 C. Baccigalupi , C. Burigana , F. Perrotta , G. De Zotti , L. La Porta , D. Maino , M. Maris , R. Paladini

The presence of a dipolar statistical anisotropy in the spectrum of cosmic microwave background (CMB) fluctuations was reported by the Wilkinson Microwave Anisotropy Probe (WMAP), and has recently been confirmed in the Planck 2013 analysis…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-29 Sugumi Kanno , Misao Sasaki , Takahiro Tanaka

We perform a cosmological analysis in which we allow the primordial power spectrum of scalar perturbations to assume a shape that is different with respect to the usual power-law, arising from the simplest models of cosmological inflation.…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-22 Stefano Gariazzo

Gravitational lensing of distant galaxies can be exploited to infer the convergence field as a function of angular position on the sky. The statistics of this field, much like that of the cosmic microwave background (CMB), can be studied to…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-07 Hee-Jong Seo , Masanori Sato , Scott Dodelson , Bhuvnesh Jain , Masahiro Takada

We model the cosmic medium as the mixture of a generalized Chaplygin gas and a pressureless matter component. Within a neo-Newtonian approach we compute the matter power spectrum. The 2dFGRS data are used to discriminate between unified…

Astrophysics · Physics 2015-05-13 J. C. Fabris , S. V. B. Goncalves , H. E. S. Velten , W. Zimdahl

We calculate the power spectrum of vacuum fluctuations of a generic scalar field in a quantum cosmological setting that is manifestly singularity-free. The power spectrum is given in terms of the usual scale invariant spectrum plus scale…

Astrophysics · Physics 2007-05-23 S. Hofmann , O. Winkler

The Cosmological Principle assumes a statistically isotropic Universe, but the Cosmic Microwave Background (CMB) exhibits some anomalous statistical features, such as the hemispherical power asymmetry, that challenge this core assumption.…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-25 Javier Carrón Duque , Mikel Martin Barandiaran , Joseba Martínez-Arrizabalaga

We investigate a set of cosmological models for which the primordial power spectrum has a large-scale power deficit. The standard power-law spectrum is subject to long-wavelength modifications described by some new parameters, resulting in…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-13 Sandro D. P. Vitenti , Patrick Peter , Antony Valentini

Using data from the SUGAR and the AGASA experiments taken during a 10 yr period with nearly uniform exposure to the entire sky, we search for large-scale anisotropy patterns in the arrival directions of cosmic rays with energies > 10^{19.6}…

In this letter we show that the presence of the long-range Coulomb force in dense stellar matter implies that the total charge cannot be associated with a chemical potential, even if it is a conserved quantity. As a further consequence, the…

Astrophysics · Physics 2008-11-26 P. Chomaz , F. Gulminelli , C. Ducoin , P. Napolitani , K. H. O. Hasnaoui

The acoustic peak in the CMB power spectrum is sensitive to causal processes and cosmological parameters in the early universe up to the time of last scattering. We provide limits on correlated spatial variations of the peak height and peak…

Astrophysics · Physics 2009-11-10 Evan P. Donoghue , John F. Donoghue

We study light propagation in the picture of semi-classical space-time that emerges in canonical quantum gravity in the loop representation. In such picture, where space-time exhibits a polymer-like structure at microscales, it is natural…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Rodolfo Gambini , Jorge Pullin

Non-linear cosmic structures contain valuable information on the expansion history of the background space-time, the nature of dark matter, and the gravitational interaction. The recently developed kinetic field theory of cosmic structure…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-18 Alexander Oestreicher , Lodovico Capuano , Sabino Matarrese , Lavinia Heisenberg , Matthias Bartelmann

A space-dependent mean for cosmological perturbations negates the ansatz of statistical homogeneity and isotropy, and hence ergodicity. In this work, we construct such a primordial mean of scalar perturbations from an alternative quantum…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-30 H. V. Ragavendra , Dipayan Mukherjee , Shiv K. Sethi

The primary results of most observations of cosmic microwave background (CMB) anisotropy are estimates of the angular power spectrum averaged through some broad band, called band-powers. These estimates are in turn what are used to produce…

Astrophysics · Physics 2016-08-25 Lloyd Knox

The Standard Cosmological Model has experienced tremendous success at reproducing observational data by assuming a universe dominated by a cosmological constant and dark matter in a flat geometry. However, several studies, based on local…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-29 Jailson S. Alcaniz , Jacinto P. Neto , Farinaldo S. Queiroz , Deivid R. da Silva , Raimindo Silva

Phase-space descriptions are used to find qualitative features of the solutions of generalized scalar field cosmologies with arbitrary potentials and arbitrary couplings to matter. Previous results are summarized and new ones are presented…

General Relativity and Quantum Cosmology · Physics 2020-12-01 Genly Leon , Felipe Orlando Franz Silva

We present a method for suppressing contributions from higher-order terms in perturbation theory, greatly increasing the amount of information which may be extracted from the matter power spectrum. In an evolved cosmological density field…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Fergus Simpson , Alan F. Heavens , Catherine Heymans

Mainly used to set constraints on cosmological parameters, CMB anisotropies can give information on primordial universe. Unfortunately, initial conditions and late time cosmology are degenerated. I focus on the effect of the shape of the…

Astrophysics · Physics 2007-05-23 Marian Douspis