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Angular anisotropy techniques for cosmic diffuse radiation maps are powerful probes, even for quite small data sets. A popular observable is the angular power spectrum; we present a detailed study applicable to any unbinned source skymap…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Sheldon S. Campbell

In recent years, some studies have drawn attention to the lack of large-angle correlations in the observed cosmic microwave background (CMB) temperature anisotropies with respect to that predicted within the standard $\Lambda$CDM model.…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-23 Gabriel R. Bengochea , Gabriel Leon

The Cosmic Microwave Background Radiation (CMB) is an invaluable probe of the conditions of the early universe. Recent measurements of its spatial anisotropy have allowed accurate determinations of several fundamental cosmological…

Astrophysics · Physics 2009-09-29 Christopher O'Dell

The likelihood function is a crucial element of parameter estimation. In analyses of galaxy overdensities and weak lensing shear, one often approximates the likelihood of the power spectrum with a Gaussian distribution. The posterior…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 L. Sun , Q. Wang , H. Zhan

The preferred shape for the primordial spectrum of curvature perturbations is determined by performing a Bayesian model selection analysis of cosmological observations. We first reconstruct the spectrum modelled as piecewise linear in \log…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-27 J. Alberto Vazquez , M. Bridges , M. P. Hobson , A. N. Lasenby

Anisotropies in the temperature of the cosmic microwave background have been detected on a range of scales by several different experiments. These anisotropies reflect the primordial spectrum of metric perturbations in the early universe.…

Astrophysics · Physics 2009-10-22 Scott Dodelson , Arthur Kosowsky

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

We present a re-analysis of the cosmic confusion hypothesis, elucidating the degree to which ``confusion'' can be expected to hold in a class of flat, adiabatic models. This allows us to devise a simple and accurate fitting function for the…

Astrophysics · Physics 2009-08-18 Martin White

The combination of detections of anisotropy in the Cosmic Microwave Background radiation and observations of the large-scale distribution of galaxies probes the primordial density fluctuations of the universe on spatial scales varying by…

Astrophysics · Physics 2008-11-26 Eric Gawiser , Joseph Silk

Experimentally distinguishing different primordial universe paradigms that lead to the Big Bang model is an outstanding challenge in modern cosmology and astrophysics. We show that a generic type of signals that exist in primordial universe…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Xingang Chen

We observationally examine cosmological models based on primordial power spectra with quantized wavevectors. Introducing a linearly quantized power spectrum with $k_0=3.225\times10^{-4}\mathrm{Mpc}^{-1}$ and spacing $\Delta k = 2.257 \times…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-18 D. J. Bartlett , W. J. Handley , A. N. Lasenby

Hot gas in filamentary structures induces CMB aniostropy through the SZ effect. Guided by results from N-body simulations, we model the morphology and gas properties of filamentary gas and determine the power spectrum of the anisotropy. Our…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Meir shimon , Sharon Sadeh , Yoel Rephaeli

The statistical properties of the primordial density perturbations has been considered in the past decade as a powerful probe of the physical processes taking place in the early universe. Within the inflationary paradigm, the properties of…

General Relativity and Quantum Cosmology · Physics 2015-06-15 Gabriel Leon , Daniel Sudarsky

The cosmic microwave background anisotropy is sensitive to the slope and amplitude of primordial energy density and gravitational wave fluctuations, the baryon density, the Hubble constant, the cosmological constant, the ionization history,…

The redshift dependence of the abundance of galaxy clusters is very sensitive to the statistical properties of primordial density perturbations. It can thus be used to probe small deviations from Gaussian initial conditions. Such deviations…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 A. M. M. Trindade , P. P. Avelino , P. T. P. Viana

We present a method for measuring the cosmic matter budget without assumptions about speculative Early Universe physics, and for measuring the primordial power spectrum P*(k) non-parametrically, either by combining CMB and LSS information…

Astrophysics · Physics 2009-10-07 Max Tegmark , Matias Zaldarriaga

We consider the properties of an ensemble of universes as function of size, where size is defined in terms of the asymptotic value of the Hubble constant (or, equivalently, the value of the cosmological constant). We assume that standard…

High Energy Physics - Theory · Physics 2009-11-07 James D. Bjorken

The Cosmic Microwave Background (CMB), which permeates the entire Universe, is the radiation left over from just 380,000 years after the Big Bang. On very large scales, the CMB radiation field is smooth and isotropic, but the existence of…

Cosmological fine-tuning has traditionally been associated with the narrowness of the intervals in which the parameters of the physical models must be located to make life possible. A more thorough approach focuses on the probability of the…

History and Philosophy of Physics · Physics 2022-04-26 Daniel Andrés Díaz-Pachón , Ola Hössjer , Robert J. Marks

Several recent papers have made claims about the detection of an asymmetric distribution of large scale power in the cosmic microwave background anisotropy as measured by the WMAP satellite. In this paper, we investigate how the estimates…

Astrophysics · Physics 2009-11-10 F. K. Hansen , A. Balbi , A. J. Banday , K. M. Gorski