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The recent measurements of the power spectrum of Cosmic Microwave Background anisotropies are consistent with the simplest inflationary scenario and big bang nucleosynthesis constraints. However, these results rely on the assumption of a…

The past, present and future of cosmic microwave background (CMB) anisotropy research is discussed, with emphasis on the Boomerang and Maxima balloon experiments. These data are combined with large scale structure (LSS) information and high…

Quantum fluctuations during inflation may be responsible for temperature anisotropies in the cosmic microwave background (CMB). Observations of CMB anisotropies can be used to falsify many currently popular models. In this paper we discuss…

Astrophysics · Physics 2009-10-30 Scott Dodelson , William H. Kinney , Edward W. Kolb

The Cosmic microwave background (CMB) anisotropies predicted by two cosmological models are compared, one of them is the standard model of general relativity with cold dark matter and cosmological constant, whereas the second model is based…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-19 Roberto Dale , Diego Sáez

We consider an alternative scenario of inflation which can account for a spatially open universe. It is similar to the old inflation in which the bubble nucleation occurs in the sea of false vacuum, but differs from it in that the second…

Astrophysics · Physics 2016-08-30 Kazuhiro Yamamoto , Misao Sasaki , Takahiro Tanaka

A broad class of dark energy models, which have been proposed in attempts at solving the cosmological constant problems, predict a late time variation of the equation of state with redshift. The variation occurs as a scalar field picks up…

Astrophysics · Physics 2009-11-10 Jaume Garriga , Levon Pogosian , Tanmay Vachaspati

We investigate the breaking of global statistical isotropy caused by a dark energy component with an energy-momentum tensor which has point symmetry, that could represent a cubic or hexagonal crystalline lattice. In such models Gaussian,…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-28 Richard Battye , Adam Moss

By using the supernovae type Ia data we study influence of the anisotropy (although low) on the evolution of the universe and compare ${\Lambda}$CDM model with 6 representative parametrizations of the recent Hubble expansion history $H(z)$.…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-05 H. Hossienkhani , H. Yousefi , N. Azimi

Assuming homogeneous isotropic Lambda-CDM cosmology allows Lambda, spatial curvature and dark matter density to be inferred from large scale structure observations such as supernovae. The purpose of this paper is to extend this to allow…

General Relativity and Quantum Cosmology · Physics 2011-02-02 Toby Wiseman , Benjamin Withers

One of the most intriguing hints of a departure from the standard cosmological model is a large-scale dipolar power asymmetry in the cosmic microwave background (CMB). If not a statistical fluke, its origins must lie in the modulation of…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-23 J. P. Zibin , D. Contreras

As an alternative explanation of the dimming of distant supernovae it has recently been advocated that we live in a special place in the Universe near the centre of a large void described by a Lemaitre-Tolman-Bondi (LTB) metric. The…

Astrophysics · Physics 2009-11-13 Juan Garcia-Bellido , Troels Haugboelle

Cosmological models assuming the scale invariance of the macroscopic empty space show an accelerated expansion, without calling for some unknown particles. Several comparisons between models and observations (tests on distances, m-z…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-04 Andre Maeder

We present a fully covariant and gauge-invariant calculation of the evolution of anisotropies in the cosmic microwave background (CMB) radiation. We use the physically appealing covariant approach to cosmological perturbations, which…

Astrophysics · Physics 2008-11-26 Anthony Challinor , Anthony Lasenby

The increasing tension between the different local direct measurements of the Hubble expansion rate and that inferred from the Cosmic Microwave Background observation by $\Lambda$-Cold-Dark-Matter model could be a smoking gun of new…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-30 Rong-Gen Cai , Jia-Feng Ding , Zong-Kuan Guo , Shao-Jiang Wang , Wang-Wei Yu

We directly compare the concordance LCDM model to the inhomogeneous matter-only alternative represented by LTB void models. To achieve a "democratic" confrontation we explore LLTB models with non-vanishing cosmological constant and perform…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-24 Valerio Marra , Mikko Paakkonen

Cosmic Microwave Background (CMB) anisotropy encodes a lot of information about our Universe. In this paper we take the ground-based CMB observations (GCMB), including the South Pole Telescope (SPT), SPTpol and the Atacama Cosmology…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Ke Wang , Qing-Guo Huang

We use the physically-consistent tilted spatially-flat and untilted non-flat $\Lambda$CDM inflation models to constrain cosmological parameter values with the Planck 2015 cosmic microwave background (CMB) anisotropy data and recent Type Ia…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-19 Chan-Gyung Park , Bharat Ratra

We propose a model of cosmological evolution of the early and late Universe which is consistent with observational data and naturally explains the origin of inflation and dark energy. We show that the de Sitter accelerated expansion of the…

General Physics · Physics 2015-06-03 Leonid Marochnik , Daniel Usikov

The influence of cosmological constant type dark energy in the early universe is investigated. This is accommodated by a new dispersion relation in de Sitter spacetime. We perform a global fitting to explore the cosmological parameters…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-30 Dong Zhao , Ming-Hua Li , Ping Wang , Zhe Chang

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